Carboxy tetrahydropyrazolopyrazine compounds for the treatment of infectious diseases

ABSTRACT

The present invention relates to compounds of the formula (I), 
     
       
         
         
             
             
         
       
         
         
           
             or pharmaceutically acceptable salts, enantiomer or diastereomer thereof, wherein R 1  to R 3  are as described above. The compounds may be useful for the treatment or prophylaxis of hepatitis B virus infection.

RELATED APPLICATIONS

This application is a Continuation of U.S. patent application Ser. No.16/247,084, now U.S. Pat. No. 10,562,905 which is a Continuation ofInternational Application No. PCT/EP2017/067319, filed Jul. 11, 2017,claiming priority to Application No. PCT/CN2016/090036, filed Jul. 14,2016 and Application No. PCT/CN2017/080438, filed Apr. 13, 2017, each ofwhich are incorporated herein by reference in its entirety.

TECHNICAL FIELD

The present invention relates to organic compounds useful for therapyand/or prophylaxis in a mammal, and in particular for treating hepatitisB virus infection, and their pharmaceutical activity, manufacture,pharmaceutical compositions containing them and their potential use asmedicaments.

The present invention relates to compounds of the formula (I),

or pharmaceutically acceptable salts, enantiomer or diastereomerthereof, wherein R¹ to R⁴ are as described below. The compounds of thisinvention are useful for the treatment or prophylaxis of hepatitis Bvirus infection.

BACKGROUND

Hepatitis B virus (HBV) infection is a major public health problemworldwide, roughly 30% of the world's population show serologicalevidence of current or past infection. Despite the introduction of asafe and effective prophylactic vaccine against the virus in the early1980s, it is estimated that there are still more than 240 millionchronic HBV carriers worldwide, a high percentage of whom willeventually develop liver cirrhosis or hepatocellular carcinoma (HCC)(WHO Hepatitis B. Fact Sheet N°204). In the 2010 Global Burden ofDisease study (R Lozano, et al. Lancet, 380 (2012), 2095-2128), HBVinfection ranked in the top health priorities in the world, and was thetenth leading cause of death (780,000 deaths per year). Recent studieshave shown that progression to liver cirrhosis and HCC in patients withchronic HBV infection is significantly associated with circulating HBVDNA levels. Thus, antiviral therapy against HBV is critical to preventthe progression to cirrhosis or development of HCC.

HBV is a small, enveloped virus that belongs to the Hepadnaviridaefamily. It contains a partly double-stranded DNA genome withapproximately 3200 base pairs. HBV have a strong preference forinfecting human hepatocytes. The life cycle begins when HBV attaches tothe host cell membrane via its envelope proteins. The precise mechanismof viral entry has not been fully elucidated. The viral relaxed circularDNA (rcDNA) containing nucleocapsids are released into the cytoplasm andtransported to the nucleus. In the nucleus, the rcDNA is repaired byboth viral and cellular enzymes to form covalently closed circular DNA(cccDNA). There is evidence that each infected cell contains 1-50 cccDNAmolecules as unique episomal minichromosomes. Both subgenomic RNA(sgRNA) and pregenomic RNA (pgRNA) are transcribed from the cccDNA usingthe cellular transcriptional machinery. After nuclear export, the pgRNAis translated into the core protein and the viral polymerase. The sgRNAis translated into the regulatory X protein and the three envelopeproteins. Self-assembly of the RNA-containing viral nucleocapsid takesplace via complex formation of the pgRNA with the core protein and thepolymerase. Inside the nucleocapsid, the pgRNA is reverse transcribedinto negative-strand DNA. rcDNA is then generated by plus-strandsynthesis from the negative-strand DNA. The nucleocapsids are eitherre-imported to the nucleus for cccDNA amplification or enveloped andreleased via the endoplasmic reticulum (ER). The reverse transcriptaselacks proofreading activity; thus, mutations of the viral genome arefrequent and result in the coexistence of genetically distinct viralspecies in infected individuals (quasispecies).

Currently, seven treatments are approved for chronic hepatitis B (CHB),including two formulations of interferon (IFN) (conventional IFN andPEG-IFN) and five nucleos(t)ide analogues (NUCs: lamivudine, adefovirdipivoxil, entecavir, telbivudine, and tenofovir disoproxil). The maindifference between immunomodulatory agents and NUCs is that PEG-IFN hasthe advantage of a finite duration of use, whereas the use of NUCs isindefinite. The major drawback of PEG-IFN is its high frequency ofadverse events. Some viral genotypes do not show good responses tointerferon therapy. Long-term use of NUCs, on the other hand, poses therisk of drug resistance. The ultimate goal of antiviral therapy for CHBis to prevent progression to cirrhosis or HCC via eradication of HBV orpersistent viral suppression. The majority of currently treated patientsfail to achieve this goal. As indicated above, nucleocapsid assembly isa critical step for HBV genome replication. As the synthesis of viralDNA takes place exclusively within the nucleocapsid, the assembly anddisassembly of nucleocapsid must be precisely regulated to ensurecorrect packaging and release of the viral genome. Nucleocapsid assemblyis an evolutionary constraint process that limits the diversity of HBV,and it is highly sensitive to even subtle molecular disturbances. Bothassembly and disassembly of nucleocapsid make the process an attractivetherapeutic target for the development of new antiviral therapiesagainst various HBV genotypes and drug resistance isolates. A few capsidrelated anti-HBV compounds have been reported. For example,heteroaryldihydropyrimidines (HAP), including compounds named Bay41-4109, Bay 38-7690 and Bay 39-5493 (Deres K. et al. Science 2003,893), and phenylpropenamide derivatives such as AT-61 and AT-130 (FeldJ. et al. Antiviral Research 2007, 168-177). Capsid has become apromising drug target with several molecules under clinical stage. Thereis still a need to develop new treatments for the prophylaxis andtreatment of hepatitis B virus infection.

SUMMARY

The present invention relates to novel compounds of formula (I),

whereinR¹ is oxooxadiazabicyclo[3.3.1]nonanyl substituted by carboxyC₁₋₆alkyl;or

oxopyrrolidinyl, said oxopyrrolidinyl being once substituted bycarboxyC₁₋₆alkyl(C₁₋₆alkyl)amino, carboxyphenyl, carboxypyridinyl,carboxyphenylamino, halocarboxyphenyl or carboxypyrrolidinyl; or twicesubstituted by carboxypyrrolidinyl and C₁₋₆alkyl;

R² is H or C₁₋₆alkyl;R³ is C₁₋₆alkyl;R⁴ is phenyl, said phenyl being three times substituted by halogen;

or pharmaceutically acceptable salt, enantiomer or diastereomer thereof.

Objects of the present invention are novel compounds of formula (I),their manufacture, medicaments based on a compound in accordance withthe invention and their production as well as the use of compounds offormula (I) as HBV inhibitors and for the treatment or prophylaxis ofHBV infection.

DETAILED DESCRIPTION Definitions

The term “C₁₋₆alkyl” denotes a monovalent linear or branched saturatedhydrocarbon group of 1 to 6 carbon atoms. In particular embodiments,C₁₋₆alkyl has 1 to 6 carbon atoms, and in more particular embodiments 1to 4 carbon atoms. Examples of C₁₋₆alkyl include methyl, ethyl, propyl,isopropyl, n-butyl, iso-butyl, sec-butyl or tert-butyl.

The term “halo” or “halogen” are used interchangeably herein and denotefluoro, chloro, bromo or iodo.

The term “carboxyphenyl” denotes a phenyl group wherein one of thehydrogen atoms of the phenyl group has been replaced by carboxy.

The term “halocarboxyphenyl” denotes a carboxyphenyl group wherein atleast one of the hydrogen atoms of the phenyl group has been replaced byhalogen. Examples of halocarboxyphenyl are chlorocarboxyphenyl,fluorocarboxyphenyl, difluorocarboxyphenyl andchlorofluorocarboxyphenyl.

The term “oxo” denotes a divalent oxygen atom ═O.

The term “diastereomer” denotes a stereoisomer with two or more centersof chirality and whose molecules are not mirror images of one another.Diastereomers have different physical properties, e.g. melting points,boiling points, spectral properties, activities and reactivities.

The term “enantiomers” denotes two stereoisomers of a compound which arenon-superimposable mirror images of one another.

The term “pharmaceutically acceptable salts” denotes salts which are notbiologically or otherwise undesirable. Pharmaceutically acceptable saltsinclude both acid and base addition salts.

The term “pharmaceutically acceptable acid addition salt” denotes thosepharmaceutically acceptable salts formed with inorganic acids such ashydrochloric acid, hydrobromic acid, sulfuric acid, nitric acid,carbonic acid, phosphoric acid, and organic acids selected fromaliphatic, cycloaliphatic, aromatic, araliphatic, heterocyclic,carboxylic, and sulfonic classes of organic acids such as formic acid,acetic acid, propionic acid, glycolic acid, gluconic acid, lactic acid,pyruvic acid, oxalic acid, malic acid, maleic acid, maloneic acid,succinic acid, fumaric acid, tartaric acid, citric acid, aspartic acid,ascorbic acid, glutamic acid, anthranilic acid, benzoic acid, cinnamicacid, mandelic acid, embonic acid, phenylacetic acid, methanesulfonicacid, ethanesulfonic acid, p-toluenesulfonic acid, and salicyclic acid.

The term “pharmaceutically acceptable base addition salt” denotes thosepharmaceutically acceptable salts formed with an organic or inorganicbase. Examples of acceptable inorganic bases include sodium, potassium,ammonium, calcium, magnesium, iron, zinc, copper, manganese, andaluminum salts. Salts derived from pharmaceutically acceptable organicnontoxic bases includes salts of primary, secondary, and tertiaryamines, substituted amines including naturally occurring substitutedamines, cyclic amines and basic ion exchange resins, such asisopropylamine, trimethylamine, diethylamine, triethylamine,tripropylamine, ethanolamine, 2-diethylaminoethanol, trimethamine,dicyclohexylamine, lysine, arginine, histidine, caffeine, procaine,hydrabamine, choline, betaine, ethylenediamine, glucosamine,methylglucamine, theobromine, purines, piperizine, piperidine,N-ethylpiperidine, and polyamine resins.

Compounds of the general formula (I) which contain one or several chiralcenters can either be present as racemates, diastereomeric mixtures, oroptically active single isomers. The racemates can be separatedaccording to known methods into the enantiomers. Particularly,diastereomeric salts which can be separated by crystallization areformed from the racemic mixtures by reaction with an optically activeacid such as e.g. D- or L-tartaric acid, mandelic acid, malic acid,lactic acid or camphorsulfonic acid.

Inhibitor of HBV

The present invention provides (i) novel compounds having the generalformula (I),

whereinR¹ is oxooxadiazabicyclo[3.3.1]nonanyl substituted by carboxyC₁₋₆alkyl;or

oxopyrrolidinyl, said oxopyrrolidinyl being once substituted bycarboxyC₁₋₆alkyl(C₁₋₆alkyl)amino, carboxyphenyl, carboxypyridinyl,carboxyphenylamino, halocarboxyphenyl or carboxypyrrolidinyl; or twicesubstituted by carboxypyrrolidinyl and C₁₋₆alkyl;

R² is H or C₁₋₆alkyl;R³ is C₁₋₆alkyl;R⁴ is phenyl, said phenyl being three times substituted by halogen;or pharmaceutically acceptable salt, enantiomer or diastereomer thereof.

A further embodiment of the present invention is a compound of formula(I), wherein R¹ is oxooxadiazabicyclo[3.3.1]nonanyl substituted bycarboxyC₁₋₆alkyl; or

oxopyrrolidinyl, said oxopyrrolidinyl being once substituted bycarboxyC₁₋₆alkyl(C₁₋₆ alkyl)amino, carboxyphenyl, carboxyphenylamino,halocarboxyphenyl or carboxypyrrolidinyl; or twice substituted bycarboxypyrrolidinyl and C₁₋₆alkyl;

R² is H or C₁₋₆alkyl;R³ is C₁₋₆alkyl;R⁴ is phenyl, said phenyl being three times substituted by halogen;or pharmaceutically acceptable salt, enantiomer or diastereomer thereof.

A further embodiment of the present invention is (ii) a compound offormula (I), wherein

-   R¹ is carboxymethyl(methyl)aminooxopyrrolidinyl,    carboxypyrrolidinyloxopyrrolidinyl,    carboxypyrrolidinyl(methyl)oxopyrrolidinyl,    carboxyphenyloxopyrrolidinyl, carboxypyridinyloxopyrrolidinyl,    carboxyphenylaminooxopyrrolidinyl,    fluorocarboxyphenyloxopyrrolidinyl or    carboxymethyloxooxadiazabicyclo[3.3.1]nonanyl;-   R² is H or methyl;-   R³ is methyl;-   R⁴ is trifluorophenyl;-   or pharmaceutically acceptable salt, enantiomer or diastereomer    thereof.

A further embodiment of the present invention is a compound of formula(I), wherein

-   R¹ is carboxymethyl(methyl)aminooxopyrrolidinyl,    carboxypyrrolidinyloxopyrrolidinyl,    carboxypyrrolidinyl(methyl)oxopyrrolidinyl,    carboxyphenyloxopyrrolidinyl, carboxyphenylaminooxopyrrolidinyl,    fluorocarboxyphenyloxopyrrolidinyl or    carboxymethyloxooxadiazabicyclo[3.3.1]nonanyl;-   R² is H or methyl;-   R³ is methyl;-   R⁴ is trifluorophenyl;-   or pharmaceutically acceptable salt, enantiomer or diastereomer    thereof.

In another embodiment of the present invention, particular compounds ofthe present invention are (iii) selected from:

(2S)-1-[1-[(6S)-6-methyl-5-[(3,4,5-trifluorophenyl)carbamoyl]-6,7-dihydro-4H-pyrazolo[1,5-a]pyrazin-3-yl]-5-oxo-pyrrolidin-3-yl]pyrrolidine-2-carboxylicacid;(2S)-1-[(2S)-2-methyl-1-[(6S)-6-methyl-5-[(3,4,5-trifluorophenyl)carbamoyl]-6,7-dihydro-4H-pyrazolo[1,5-a]pyrazin-3-yl]-5-oxo-pyrrolidin-3-yl]pyrrolidine-2-carboxylicacid;2-[methyl-[1-[(6S)-6-methyl-5-[(3,4,5-trifluorophenyl)carbamoyl]-6,7-dihydro-4H-pyrazolo[1,5-a]pyrazin-3-yl]-5-oxo-pyrrolidin-3-yl]amino]aceticacid;(2R)-1-[(2S)-2-methyl-1-[(6S)-6-methyl-5-[(3,4,5-trifluorophenyl)carbamoyl]-6,7-dihydro-4H-pyrazolo[1,5-a]pyrazin-3-yl]-5-oxo-pyrrolidin-3-yl]pyrrolidine-2-carboxylicacid;1-[1-[(6S)-6-methyl-5-[(3,4,5-trifluorophenyl)carbamoyl]-6,7-dihydro-4H-pyrazolo[1,5-a]pyrazin-3-yl]-5-oxo-pyrrolidin-3-yl]pyrrolidine-3-carboxylicacid;(2S)-1-[1-[(6S,7S)-6,7-dimethyl-5-[(3,4,5-trifluorophenyl)carbamoyl]-6,7-dihydro-4H-pyrazolo[1,5-a]pyrazin-3-yl]-5-oxo-pyrrolidin-3-yl]pyrrolidine-2-carboxylicacid;2-[1-[(6S)-6-methyl-5-[(3,4,5-trifluorophenyl)carbamoyl]-6,7-dihydro-4H-pyrazolo[1,5-a]pyrazin-3-yl]-5-oxo-pyrrolidin-3-yl]benzoicacid;3-[1-[(6S)-6-methyl-5-[(3,4,5-trifluorophenyl)carbamoyl]-6,7-dihydro-4H-pyrazolo[1,5-a]pyrazin-3-yl]-5-oxo-pyrrolidin-3-yl]benzoicacid;(2R)-1-[1-[(6S)-6-methyl-5-[(3,4,5-trifluorophenyl)carbamoyl]-6,7-dihydro-4H-pyrazolo[1,5-a]pyrazin-3-yl]-5-oxo-pyrrolidin-3-yl]pyrrolidine-2-carboxylicacid;3-fluoro-2-[1-[(6S)-6-methyl-5-[(3,4,5-trifluorophenyl)carbamoyl]-6,7-dihydro-4H-pyrazolo[1,5-a]pyrazin-3-yl]-5-oxo-pyrrolidin-3-yl]benzoicacid;2-fluoro-6-[1-[(6S)-6-methyl-5-[(3,4,5-trifluorophenyl)carbamoyl]-6,7-dihydro-4H-pyrazolo[1,5-a]pyrazin-3-yl]-5-oxo-pyrrolidin-3-yl]benzoicacid;2-[[1-[(6S)-6-methyl-5-[(3,4,5-trifluorophenyl)carbamoyl]-6,7-dihydro-4H-pyrazolo[1,5-a]pyrazin-3-yl]-5-oxo-pyrrolidin-3-yl]amino]benzoicacid;2-[7-[(6S)-6-methyl-5-[(3,4,5-trifluorophenyl)carbamoyl]-6,7-dihydro-4H-pyrazolo[1,5-a]pyrazin-3-yl]-6-oxo-3-oxa-7,9-diazabicyclo[3.3.1]nonan-9-yl]aceticacid;4-fluoro-2-[1-[(6S)-6-methyl-5-[(3,4,5-trifluorophenyl)carbamoyl]-6,7-dihydro-4H-pyrazolo[1,5-a]pyrazin-3-yl]-5-oxo-pyrrolidin-3-yl]benzoicacid;5-fluoro-2-[1-[(6S)-6-methyl-5-[(3,4,5-trifluorophenyl)carbamoyl]-6,7-dihydro-4H-pyrazolo[1,5-a]pyrazin-3-yl]-5-oxo-pyrrolidin-3-yl]benzoicacid;4-[1-[(6S)-6-methyl-5-[(3,4,5-trifluorophenyl)carbamoyl]-6,7-dihydro-4H-pyrazolo[1,5-a]pyrazin-3-yl]-5-oxo-pyrrolidin-3-yl]benzoicacid;6-[1-[(6S)-6-methyl-5-[(3,4,5-trifluorophenyl)carbamoyl]-6,7-dihydro-4H-pyrazolo[1,5-a]pyrazin-3-yl]-5-oxo-pyrrolidin-3-yl]pyridine-2-carboxylicacid; and2-[1-[(6S)-6-methyl-5-[(3,4,5-trifluorophenyl)carbamoyl]-6,7-dihydro-4H-pyrazolo[1,5-a]pyrazin-3-yl]-5-oxo-pyrrolidin-3-yl]pyridine-3-carboxylicacid.

Synthesis

The compounds of the present invention can be prepared by anyconventional means. Suitable processes for synthesizing these compoundsas well as their starting materials are provided in the schemes belowand in the examples. All substituents, in particular, R¹ to R⁴ are asdefined above unless otherwise indicated. Furthermore, and unlessexplicitly otherwise stated, all reactions, reaction conditions,abbreviations and symbols have the meanings well known to a person ofordinary skill in organic chemistry.

Compound of formula IV (ring A) is oxooxadiazabicyclo[3.3.1]nonanesubstituted by carboxyC₁₋₆alkyl; or oxopyrrolidine, said oxopyrrolidinebeing once substituted by carboxyC₁₋₆alkyl(C₁₋₆alkyl)amino,carboxyphenyl, carboxyphenylamino, halocarboxyphenyl orcarboxypyrrolidinyl, or twice substituted by carboxypyrrolidinyl andC₁₋₆alkyl. X is bromo or iodo.

As depicted in Scheme 1, the synthesis of compounds of the presentinvention could be started from bicyclic compound of formula (II), whichwas treated with halogenating agents, such as N-iodosuccinimide orN-bromosuccinimide, to give compound of formula (III). Coupling reactionbetween compound of formula (III) and compound of formula (IV) in thepresence of copper catalyst, such as CuI, afforded compound of formula(V). The following Boc-deprotection in an acidic condition such asHCl/EtOAc or TFA/DCM and urea formation with amine R³NH₂ in the presenceof a phosgene equivalent, such as triphosgene and carbonyldiimidazolecould afford final compound of formula (I). In the aforementioned ureaformation reaction, a suitable isocyanate or phenyl carbamate was alsoapplied (Padiya, K. J. et al. Org Lett. 2012, 14, 2814 and referencescited therein).

This invention also relates to a process for the preparation of acompound of formula (I) comprising the following reaction:

(a) the reaction of compound of formula (V),

with an acid followed by urea formation with amine R⁴NH₂ in the presenceof a phosgene equivalent;

wherein R¹ and R⁴ are defined above.

In step (a), the acid can be for example HCl/EtOAc and TFA/DCM; phosgeneequivalent can be for example triphosgene and carbonyldiimidazole.

A compound of formula (I) when manufactured according to the aboveprocess is also an object of the invention.

Pharmaceutical Compositions and Administration

Another embodiment provides pharmaceutical compositions or medicamentscontaining the compounds of the invention and a therapeutically inertcarrier, diluent or excipient, as well as methods of using the compoundsof the invention to prepare such compositions and medicaments. In oneexample, compounds of formula (I) may be formulated by mixing at ambienttemperature at the appropriate pH, and at the desired degree of purity,with physiologically acceptable carriers, i.e., carriers that arenon-toxic to recipients at the dosages and concentrations employed intoa galenical administration form. The pH of the formulation dependsmainly on the particular use and the concentration of compound, butpreferably ranges anywhere from about 3 to about 8. In one example, acompound of formula (I) is formulated in an acetate buffer, at pH 5. Inanother embodiment, the compounds of formula (I) are sterile. Thecompound may be stored, for example, as a solid or amorphouscomposition, as a lyophilized formulation or as an aqueous solution.

Compositions are formulated, dosed, and administered in a fashionconsistent with good medical practice. Factors for consideration in thiscontext include the particular disorder being treated, the particularmammal being treated, the clinical condition of the individual patient,the cause of the disorder, the site of delivery of the agent, the methodof administration, the scheduling of administration, and other factorsknown to medical practitioners. The “effective amount” of the compoundto be administered will be governed by such considerations, and is theminimum amount necessary to the suppression of serum HBV DNA levels, orHBeAg seroconversion to HBeAb, or HBsAg loss, or normalization ofalanine aminotransferase levels and improvement in liver histology. Forexample, such amount may be below the amount that is toxic to normalcells, or the mammal as a whole.

In one example, the pharmaceutically effective amount of the compound ofthe invention administered parenterally per dose will be in the range ofabout 0.01 to 100 mg/kg, alternatively about 0.1 to 20 mg/kg of patientbody weight per day, with the typical initial range of compound usedbeing 0.3 to 15 mg/kg/day. In another embodiment, oral unit dosageforms, such as tablets and capsules, contain from about 0.1 to about1000 mg of the compound of the invention.

The compounds of the invention may be administered by any suitablemeans, including oral, topical (including buccal and sublingual),rectal, vaginal, transdermal, parenteral, subcutaneous, intraperitoneal,intrapulmonary, intradermal, intrathecal and epidural and intranasal,and, if desired for local treatment, intralesional administration.Parenteral infusions include intramuscular, intravenous, intraarterial,intraperitoneal, or subcutaneous administration.

The compounds of the present invention may be administered in anyconvenient administrative form, e.g., tablets, powders, capsules,solutions, dispersions, suspensions, syrups, sprays, suppositories,gels, emulsions, patches, etc. Such compositions may contain componentsconventional in pharmaceutical preparations, e.g., diluents, carriers,pH modifiers, sweeteners, bulking agents, and further active agents.

A typical formulation is prepared by mixing a compound of the presentinvention and a carrier or excipient. Suitable carriers and excipientsare well known to those skilled in the art and are described in detailin, e.g., Ansel, Howard C., et al., Ansel's Pharmaceutical Dosage Formsand Drug Delivery Systems. Philadelphia: Lippincott, Williams & Wilkins,2004; Gennaro, Alfonso R., et al. Remington: The Science and Practice ofPharmacy. Philadelphia: Lippincott, Williams & Wilkins, 2000; and Rowe,Raymond C. Handbook of Pharmaceutical Excipients. Chicago,Pharmaceutical Press, 2005. The formulations may also include one ormore buffers, stabilizing agents, surfactants, wetting agents,lubricating agents, emulsifiers, suspending agents, preservatives,antioxidants, opaquing agents, glidants, processing aids, colorants,sweeteners, perfuming agents, flavoring agents, diluents and other knownadditives to provide an elegant presentation of the drug (i.e., acompound of the present invention or pharmaceutical composition thereof)or aid in the manufacturing of the pharmaceutical product (i.e.,medicament).

An example of a suitable oral dosage form is a tablet containing about0.1 mg to 1000 mg of the compound of the invention compounded with about30 mg to 90 mg anhydrous lactose, about 5 mg to 40 mg sodiumcroscarmellose, about 5 mg to 30 mg polyvinylpyrrolidone (PVP) K30, andabout 1 mg to 10 mg magnesium stearate. The powdered ingredients arefirst mixed together and then mixed with a solution of the PVP. Theresulting composition can be dried, granulated, mixed with the magnesiumstearate and compressed to tablet form using conventional equipment. Anexample of an aerosol formulation can be prepared by dissolving thecompound, for example 5 mg to 400 mg, of the invention in a suitablebuffer solution, e.g. a phosphate buffer, adding a tonicifier, e.g. asalt such sodium chloride, if desired. The solution may be filtered,e.g., using a 0.2 micron filter, to remove impurities and contaminants.

An embodiment, therefore, includes a pharmaceutical compositioncomprising a compound of formula (I), or a stereoisomer orpharmaceutically acceptable salt thereof. In a further embodimentincludes a pharmaceutical composition comprising a compound of formula(I), or a stereoisomer or pharmaceutically acceptable salt thereof,together with a pharmaceutically acceptable carrier or excipient.

Indications and Methods of Treatment

The compounds of the invention can inhibit HBV's DNA synthesis andreduce HBV DNA levels. Accordingly, the compounds of the invention areuseful for the treatment or prophylaxis of HBV infection.

The invention relates to the use of a compound of formula (I) for thetreatment or prophylaxis of HBV infection.

The use of a compound of formula (I) for the preparation of medicamentsuseful in the treatment or prophylaxis diseases that are related to HBVinfection is an object of the invention.

The invention relates in particular to the use of a compound of formula(I) for the preparation of a medicament for the treatment or prophylaxisof HBV infection.

Another embodiment includes a method for the treatment or prophylaxis ofHBV infection which method comprises administering an effective amountof a compound of formula (I), a stereoisomer, tautomer, prodrug orpharmaceutically acceptable salt thereof.

EXAMPLES

The invention will be more fully understood by reference to thefollowing examples. They should not, however, be construed as limitingthe scope of the invention.

Abbreviations used herein are as follows:

-   -   CbzCl: benzyl chloroformate    -   DCE: 1,2-dichloroethylene    -   DIAD: diisopropyl azodicarboxylate    -   DIPEA: N,N-diisopropylethylamine    -   EA or EtOAc: ethyl acetate    -   EC₅₀: half maximal effective concentration    -   HPLC: high performance liquid chromatography    -   LCMS liquid chromatography-mass spectrometry    -   MS: mass spectrometry    -   MsCl: methanesulfonyl chloride    -   NIS: N-iodosuccinimide    -   PE: petroleum ether    -   prep-HPLC: preparative high performance liquid chromatography    -   prep-TLC: preparative thin layer chromatography    -   psi: pounds per square inch    -   SFC: supercritical fluid chromatography    -   TEA: trimethylamine    -   t-BuXPhos:        2-di-tert-butylphosphino-2′,4′,6′-triisopropylbiphenyl    -   TMG: 1,1,3,3-tetramethylguanidine    -   Pd₂(dba)₃: Tris(dibenzylideneacetone)dipalladium(0)    -   pgRNA: pre-genomic RNA    -   qPCR: quantitative polymerase chain reaction

v/v volume ratio

General Experimental Conditions

Intermediates and final compounds were purified by flash chromatographyusing one of the following instruments: i) Biotage SP1 system and theQuad 12/25 Cartridge module. ii) ISCO combi-flash chromatographyinstrument. Silica gel Brand and pore size: i) KP-SL 60 Å, particlesize: 40-60 μM; ii) CAS registry NO: Silica Gel: 63231-67-4, particlesize: 47-60 micron silica gel; iii) ZCX from Qingdao Haiyang ChemicalCo., Ltd, pore: 200-300 or 300-400.

Intermediates and final compounds were purified by preparative HPLC onreversed phase column using X Bridge™ Perp C₁₈ (5 μm, OBD™ 30×100 mm)column or SunFire™ Perp C₁₈ (5 μm, OBD™ 30×100 mm) column. Waters AutoPpurification System (Column: XBridge™ Prep-C18, 30×100 mm, SampleManager 2767, Pump 2525, Detector: Micromass ZQ and UV 2487, solventsystem: acetonitrile and 0.1% ammonium hydroxide in water).

LC/MS spectra of compounds were obtained using a LC/MS (Waters™ Alliance2795-Micromass ZQ). LC/MS conditions were as follows (running time 6mins):

Acidic condition: A: 0.1% formic acid in H₂O; B: 0.1% formic acid inacetonitrile;

Basic condition: A: 0.1% NH₃·H₂O in 1H₂O; B: acetonitrile;

Neutral condition: A: H₂O; B: acetonitrile.

Mass spectra (MS): generally only ions which indicate the parent massare reported, and unless otherwise stated the mass ion quoted is thepositive mass ion (M+H)⁺.

The microwave assisted reactions were carried out in a Biotage InitiatorSixty or CEM Discover.

NMR Spectra were obtained using Bruker Avance 400 MHz.

All reactions involving air-sensitive reagents were performed under anargon atmosphere.

Reagents were used as received from commercial suppliers without furtherpurification unless otherwise noted.

The following examples are intended to illustrate the meaning of thepresent invention but should by no means represent a limitation withinthe meaning of the present invention.

Preparative Examples

The invention will be more fully understood by reference to thefollowing examples. They should not, however, be construed as limitingthe scope of the invention.

Intermediate I-1 tert-Butyl(6S)-3-iodo-6-methyl-6,7-dihydro-4H-pyrazolo[1,5-a]pyrazine-5-carboxylate

Intermediate I-1 was prepared according to the following scheme:

Step 1: Preparation of tert-butylN-[(1S)-2-hydroxy-1-methyl-ethyl]-N-(1H-pyrazol-5-ylmethyl)carbamate(Compound I-1b)

To a solution of 1H-pyrazole-5-carbaldehyde (compound I-1a, 54.0 g,562.5 mmol) in MeOH (300 mL) was added (2S)-2-aminopropan-1-ol (41.2 g,675 mmol) and the reaction mixture was stirred at 25° C. for 1 hour.NaBH₄ (25.9 g, 675.0 mmol) was added at 0° C. and the reaction mixturewas stirred for another 1 hour followed by the addition of H₂O (300 mL)and Boc₂O (147.1 g, 675.0 mmol). The resulting mixture was stirred atroom temperature for 12 hours, and extracted with EtOAc (600 mL). Theorganic layer was dried over Na₂SO₄, filtered and concentrated. Theresidue was purified by column chromatography (eluting with 0%˜5% MeOHin DCM) to afford compound I-1b (80 g) as a colorless oil. LCMS (M+H⁺):334.

Step 2: Preparation of[(2S)-2-[tert-butoxycarbonyl(1H-pyrazol-5-ylmethyl)amino]propyl]methanesulfonate (Compound I-1c)

To a mixture of tert-butyl N-[(1S)-2-hydroxy-1-methyl-ethyl]-N-(1H-pyrazol-5-ylmethyl)carbamate(compound I-1b, 80.0 g, 117.2 mmol) and Et₃N (100.5 g, 995.6 mmol) inDCM (800 mL) was added MsCl (57.3 g, 497.8 mmol) slowly at 0° C. Theresulting mixture was stirred at room temperature for 2 hours, thenwashed with water (500 mL), brine (500 mL), and dried over Na₂SO₄. Theorganic layer was concentrated to afford compound I-1c (100 g, crude),which was used directly in next step.

Step 3: Preparation of tert-butyl(6S)-6-methyl-6,7-dihydro-4H-pyrazolo[1,5-a]pyrazine-5-carboxylate(Compound I-1d)

To a solution of[(2S)-2-[tert-butoxycarbonyl(1H-pyrazol-5-ylmethyl)amino]propyl]methanesulfonate(compound I-1c, 100.0 g, 313.4 mmol) in DMF (1000 mL) was added NaH(15.0 g, 376.2 mmol) in portions at 0° C. The reaction mixture was thenstirred at room temperature for 12 hours, poured into water (2000 mL)and extracted with EtOAc (1000 mL) twice. The combined organic layer wasconcentrated, and the residue was purified by column chromatography(eluting with 10%˜80% EtOAc in petroleum ether) to afford compound I-1d(18.0 g) as a colorless oil. LCMS (M+H⁺): 238.

Step 4: Preparation of tert-butyl(6S)-3-iodo-6-methyl-6,7-dihydro-4H-pyrazolo[1,5-a]pyrazine-5-carboxylate(Intermediate I-1)

To a solution of tert-butyl6-methyl-6,7-dihydro-4H-pyrazolo[1,5-a]pyrazine-5-carboxylate (compound53c, 3.3 g, 14.8 mmol) in CH₃CN (40 mL) was added NIS (5.0 g, 22.1 mmol)slowly. The reaction mixture was stirred at room temperature for 16hours and then extracted with EtOAc (50 mL), washed with brine (50 mL).The organic layer was dried over Na₂SO₄ and concentrated, and theresidue was purified by column chromatography (eluting with 10%˜80%EtOAc in petroleum ether) to afford intermediate I-1 (4.8 g) as a whitesolid.

Intermediate I-2 tert-Butyl(6S,7S)-3-iodo-6,7-dimethyl-6,7-dihydro-4H-pyrazolo[1,5-a]pyrazine-5-carboxylate

Intermediate I-2 was prepared according to the following scheme:

Step 1: Preparation of (4R,5R)-4,5-dimethyl-1,3,2-dioxathiolane2,2-dioxide (Compound I-2b)

A solution of SOCl₂ (7.26 g, 4.45 mL, 61 mmol) in DCM (50 mL) was addeddropwise to a stirred mixture of (2R,3R)-butane-2,3-diol (5 g, 55.5mmol), imidazole (18.9 g, 277 mmol) and triethylamine (19.6 g, 27.1 mL,194 mmol) in DCM (200 mL) at 0° C., and the reaction mixture was stirredfor 1 hour at 0° C. The reaction mixture was quenched with H₂O andextracted twice with DCM. The combined organic layer was washed withH₂O, dried over MgSO₄, filtered and concentrated to give a residue. To astirred solution of the crude residue in acetonitrile (200 mL) at 0° C.were added sodium periodate (17.8 g, 83.2 mmol), water (150 mL) andrhodium (III) chloride (1.16 g, 5.55 mmol) sequentially and the reactionmixture was stirred at 0° C. for 3 hours. The two layers were separatedand the aqueous layer was extracted three times with EtOAc. The combinedorganic layer was washed with saturated aqueous NaHCO₃ and brine, andthen dried over MgSO₄, filtered and concentrated to give compound I-2bas a colorless oil (8 g).

Step 2: Preparation of (2R,3S)-3-(4-bromo-1H-pyrazol-1-yl)butan-2-ol(Compound I-2c)

A mixture of (4R,5R)-4,5-dimethyl-1,3,2-dioxathiolane 2,2-dioxide(compound I-2b, 8 g, 52.6 mmol), 4-bromo-1H-pyrazole (11.6 g, 78.9 mmol)and Cs₂CO₃ (34.3 g, 105 mmol) in DMF (50 mL) was stirred at roomtemperature for 16 hours. The reaction mixture was filtered andconcentrated. The resulting residue was taken up in 400 mL of THF/50%aq. H₂SO₄ (v/v 1/2), and stirred vigorously for 48 hours. The reactionmixture was then carefully basified with 10 M aqueous NaOH solution, andthe layers were separated. The aqueous layer was extracted twice withDCM, and the combined organic layer was washed with brine, dried overMgSO₄, filtered and concentrated to give compound I-2c as a colorlessoil (8 g). LCMS (M+H⁺): 219

Step 3: Preparation of2-((2S,3S)-3-(4-bromo-1H-pyrazol-1-yl)butan-2-yl)isoindoline-1,3-dione(Compound I-2d)

To a mixture of (2R,3S)-3-(4-bromo-1H-pyrazol-1-yl)butan-2-ol (compoundI-2c, 8 g, 36.5 mmol), isoindoline-1,3-dione (5.91 g, 40.2 mmol) andtriphenylphosphine (12.5 g, 47.5 mmol) in THF (75 mL) was added DIAD(11.1 g, 54.8 mmol) dropwise at room temperature. Then the reactionmixture was stirred at room temperature for 2 hours, and concentrated invacuo. The crude product was purified by flash chromatography (silicagel, 0% to 50% EtOAc in hexanes) to give compound I-2d as a white solid(5 g). LCMS (M+H⁺): 348

Step 4: Preparation of (2S,3S)-3-(4-bromo-1H-pyrazol-1-yl)butan-2-amine(Compound I-2e)

A mixture of2-((2S,3S)-3-(4-bromo-1H-pyrazol-1-yl)butan-2-yl)isoindoline-1,3-dione(compound I-2d, 5 g, 14.4 mmol) and Hydrazine hydrate (7.19 g, 144 mmol)in MeOH (50 mL) was stirred at 80° C. for 15 hours. The reaction mixturewas concentrated in vacuo. The residue was dissolved in DCM, the solidwas filtered off and the filtrate was concentrated to give compound I-2eas a slight yellow oil (3 g). LCMS (M+H⁺): 218

Step 5: Preparation of(2S,3S)—N-benzyl-3-(4-bromo-1H-pyrazol-1-yl)butan-2-amine (CompoundI-2f)

A mixture of (2S,3S)-3-(4-bromo-1H-pyrazol-1-yl)butan-2-amine (compoundI-2e, 3 g, 13.8 mmol) and benzaldehyde (1.61 g, 15.1 mmol) in MeOH (50mL) was stirred for 2 hours at room temperature. Then sodium borohydride(624 mg, 16.5 mmol) was added slowly at 0° C. in 30 mins and thereaction mixture was stirred at room temperature for another 30 mins.The reaction mixture was poured into 100 mL of H₂O and extracted withEtOAc (100 mL) twice. The combined organic layer was dried over Na₂SO₄and then concentrated in vacuo. The crude product was purified by flashchromatography (silica gel, 0% to 50% EtOAc in hexanes) to give compoundI-2f as light yellow oil (4 g). LCMS (M+H⁺): 308

Step 6: Preparation of(6S,7S)-5-benzyl-3-bromo-6,7-dimethyl-4,5,6,7-tetrahydropyrazolo[1,5-a]pyrazine(Compound I-2g)

To a stirred solution of(2S,3S)—N-benzyl-3-(4-bromo-1H-pyrazol-1-yl)butan-2-amine (compoundI-2f, 4 g, 13 mmol) in acetonitrile (50 mL) was added paraformaldehyde(1.95 g, 64.9 mmol) and 2,2,2-trifluoroacetic acid (296 mg, 2.6 mmol),and the reaction mixture was stirred at 70° C. for 6 hours. The reactionmixture was concentrated and the residue was then taken up in EtOAc, andwashed with NaHCO₃ aq. solution and brine. The organic layer wasconcentrated and the residue was purified on a silica gel column(heptane: EtOAc 1:0 to 9:1) to give compound I-2g as a colorless oil(2.3 g). LCMS (M+H⁺): 320

Step 7: Preparation of tert-butyl(6S,7S)-6,7-dimethyl-6,7-dihydro-4H-pyrazolo[1,5-a]pyrazine-5-carboxylate(Compound I-2h)

A mixture of(6S,7S)-5-benzyl-3-bromo-6,7-dimethyl-4,5,6,7-tetrahydropyrazolo[1,5-a]pyrazine(compound I-2g, 1.5 g, 4.68 mmol), di-tert-butyl dicarbonate (2.18 mL,9.37 mmol) and Pd(OH)₂/C (329 mg) in MeOH (50 mL) was heated to 50° C.and stirred for 15 h under hydrogen. Then the solid was filtered off andthe filtrate was concentrated. The residue was dissolved in THF/MeOH(v/v 5:1, 50 ml), di-tert-butyl dicarbonate (2.18 ml, 9.37 mmol) andNa₂CO₃ (496 mg, 4.68 mmol) were added. The reaction mixture was stirredat room temperature for 16 hours and then filtered through celite, thefiltrate was concentrated and the crude material was purified by flashchromatography (silica gel, 10% to 50% EtOAc in hexanes, EtOAc contain10% MeOH). LCMS (M+H⁺): 252.

Step 8: Preparation of tert-butyl(6S,7S)-3-iodo-6,7-dimethyl-6,7-dihydro-4H-pyrazolo[1,5-a]pyrazine-5-carboxylate(Intermediate I-2) To a solution of (6S,7S)-tert-butyl6,7-dimethyl-6,7-dihydropyrazolo[1,5-a]pyrazine-5(4H)-carboxylate(compound I-2h, 1.2 g, 4.77 mmol) in MeCN (20 mL) was added NIS (1.61 g,7.16 mmol) and then stirred at room temperature for 16 hours. Thereaction mixture was quenched with aq. NaHSO₃, extracted with EtOAc,dried and concentrated. The crude material was purified by flashchromatography (silica gel, 0% to 50% EtOAc in hexanes) to giveintermediate I-2 as colorless oil, 1.2 g. LCMS (M+H⁺): 378.

Intermediate I-3 Phenyl N-(3,4,5-trifluorophenyl)carbamate

Intermediate I-3 was prepared according to the following scheme:

To a solution of 3,4,5-trifluoroaniline (1.47 g, 10 mmol) in DCM (30 mL)was added DIPEA (2.06 mL, 12 mmol), followed by adding phenylchloroformate (1.38 mL, 11 mmol) dropwise at 0° C. After addition thereaction mixture was warmed to room temperature and stirred overnight.The reaction mixture was diluted with DCM, washed with water. Theorganic phase was separated, dried over Na₂SO₄ and concentrated. Theresidue was purified by column to give intermediate I-3 as a whitesolid, 1.87 g. LCMS (M+H⁺): 268.

Example 1(2S)-1-[1-[(6S)-6-methyl-5-[(3,4,5-trifluorophenyl)carbamoyl]-6,7-dihydro-4H-pyrazolo[1,5-a]pyrazin-3-yl]-5-oxo-pyrrolidin-3-yl]pyrrolidine-2-carboxylicacid

The title compound was prepared according to the following scheme:

Step 1: Preparation of methyl(2S)-1-(5-oxopyrrolidin-3-yl)pyrrolidine-2-carboxylate (Compound 1b)

A mixture of pyrrolidine-2,4-dione (compound 1a, 200 mg, 2.02 mmol),methyl (2S)-pyrrolidine-2-carboxylate (334 mg, 2.02 mmol) and Pd/C (100mg) in MeOH (20 mL) was stirred at room temperature for 40 hours under50 psi H₂ atmosphere. The reaction mixture was filtered and the filtratewas concentrated to give compound 1b (400 mg, crude) as a brown oil.

Step 2: Preparation of tert-butyl(6S)-3-[4-[(2S)-2-methoxycarbonylpyrrolidin-1-yl]-2-oxo-pyrrolidin-1-yl]-6-methyl-6,7-dihydro-4H-pyrazolol[1,5-a]pyrazine-5-carboxylate(Compound 1c)

A mixture of methyl (2S)-1-(5-oxopyrrolidin-3-yl)pyrrolidine-2-carboxylate (compound 1b, 400mg), tert-butyl(6S)-3-iodo-6-methyl-6,7-dihydro-4H-pyrazolo[1,5-a]pyrazine-5-carboxylate(Intermediate I-1, 684 mg, 1.88 mmol),(1R,2R)—N1,N2-dimethylcyclohexane-1,2-diamine (54 mg, 0.38 mmol), CuI(72 mg, 0.38 mmol) and K₃PO₄ (800 mg, 3.78 mmol) in dioxane (20 mL) wasdegassed and refilled with N₂, and stirred at 110° C. under N₂ for 16hours. The reaction mixture was filtered, the filtrate was concentratedand the crude product was purified by prep-HPLC to give compound 1c (200mg) as a white solid. LCMS (M+H⁺): 448.3.

Step 3: Preparation of methyl(2S)-1-[1-[(6S)-6-methyl-5-[(3,4,5-trifluorophenyl)carbamoyl]-6,7-dihydro-4H-pyrazolo[1,5-a]pyrazin-3-yl]-5-oxo-pyrrolidin-3-yl]pyrrolidine-2-carboxylate(Compound 1d)

To a solution of tert-butyl(6S)-3-[4-[(2S)-2-methoxycarbonylpyrrolidin-1-yl]-2-oxo-pyrrolidin-1-yl]-6-methyl-6,7-dihydro-4H-pyrazolo[1,5-a]pyrazine-5-carboxylate(compound 1c, 200 mg, 0.447 mmol) in MeOH (10 mL) was added a solutionof HCl in MeOH (4 M, 5 mL, 20 mmol). The reaction mixture was stirred atroom temperature for 2 h, and then concentrated to give a crude material(0.18 g) as a brown solid. The solid was dissolved in DMF (4 mL), towhich were added DIPEA (0.16 g, 1.18 mmol) and phenylN-(3,4,5-trifluorophenyl)carbamate (Intermediate I-3, 0.15 g, 0.56mmol). The reaction mixture was stirred at 30° C. for 12 h, diluted withH₂O (20 mL), and extracted three times with EtOAc (20 mL each). Thecombined organic phase was concentrated and the obtained residue waspurified by prep-TLC (DCM/MeOH=10/1) to give compound 1d (0.15 g) as abrown solid. LCMS (M+H⁺): 521.4

Step 4: Preparation of(2S)-1-[1-[(6S)-6-methyl-5-[(3,4,5-trifluorophenyl)carbamoyl]-6,7-dihydro-4H-pyrazol[1,5-a]pyrazin-3-yl]-5-oxo-pyrrolidin-3-yl]pyrrolidine-2-carboxylicacid (Example 1)

To a mixture of methyl(2S)-1-[1-[(6S)-6-methyl-5-[(3,4,5-trifluorophenyl)carbamoyl]-6,7-dihydro-4H-pyrazolo[1,5-a]pyrazin-3-yl]-5-oxo-pyrrolidin-3-yl]pyrrolidine-2-carboxylate(compound 1d, 150 mg, 0.28 mmol) in MeOH (2 mL) and H₂O (1 mL) was addedLiOH (28 mg, 1.15 mmol), the reaction mixture was stirred at roomtemperature for 2 h, then acidified with 2 M aqueous HCl solution topH=5, and concentrated. The obtained residue was purified by prep-HPLCto give Example 1 (30 mg) as a white solid. LCMS (M+H⁺): 507.2, ¹H NMR(400 MHz, METHANOL-d₄) δ ppm 7.71-7.61 (m, 1H), 7.40-7.24 (m, 2H),5.15-5.05 (m, 1H), 5.05-4.92 (m, 1H), 4.58-4.45 (m, 1H), 4.40-3.90 (m,6H), 3.90-3.75 (m, 1H), 3.26-3.15 (m, 1H), 3.15-2.85 (m, 2H), 2.56-2.42(m, 1H), 2.31-2.20 (m, 1H), 2.20-2.04 (m, 1H), 2.04-1.88 (m, 1H),1.32-1.24 (m, 3H)

Example 2(2S)-1-[(2S)-2-methyl-1-[(6S)-6-methyl-5-[(3,4,5-trifluorophenyl)carbamoyl]-6,7-dihydro-4H-pyrazolo[1,5-a]pyrazin-3-yl]-5-oxo-pyrrolidin-3-yl]pyrrolidine-2-carboxylicacid

The title compound was prepared according to the following scheme:

Step 1: Preparation of tert-butyl(2S)-3-[(2S)-2-methoxycarbonylpyrrolidin-1-yl]-2-methyl-5-oxo-pyrrolidine-1-carboxylate(Compound 2b)

To the mixture of tert-butyl (2S)-2-methyl-3,5-dioxo-pyrrolidine-1-carboxylate (500 mg, 2.34 mmol, forits synthesis, refer to Hosseini, M. et al Org. Letters 2006, 8, 2103)in DCE (10 mL) was added methyl (2S)-pyrrolidine-2-carboxylate (395 mg,2.81 mmol) and AcOH (5 drops), the reaction mixture was stirred for 5hours at 40° C., then NaCNBH₃ (294 mg, 4.68 mmol) was added. Thereaction mixture was stirred at 40° C. for 12 hours and then dilutedwith EtOAc (100 mL), filtered, and the filtrate was concentrated, theresidue was purified by column chromatography (PE/EtOAc=1/1) to givecrude compound 2b (1.2 g, crude) as a colorless oil.

Step 2: Preparation of methyl(2S)-1-[(2S)-2-methyl-5-oxo-pyrrolidin-3-yl]pyrrolidine-2-carboxylate(Compound 2c)

To a mixture of tert-butyl(2S)-3-[(2S)-2-methoxycarbonylpyrrolidin-1-yl]-2-methyl-5-oxo-pyrrolidine-1-carboxylate(compound 2b, 1.2 g, crude) in EtOAc (5 mL) was added HCl (20 mL L, 80mmol, 4 M in dioxane), the reaction mixture was stirred at roomtemperature for 2 hours. The reaction mixture was concentrated and theresidue was purified by prep-HPLC to give compound 2c (186 mg) as acolorless oil. LCMS (M+H⁺): 227.0.

Step 3: tert-butyl(6S)-3-[(2S)-3-[(2S)-2-methoxycarbonylpyrrolidin-1-yl]-2-methyl-5-oxo-pyrrolidin-1-yl]-6-methyl-6,7-dihydro-4H-pyrazolo[1,5-a]pyrazine-5-carboxylate(Compound 2d)

To a solution of tert-butyl (6S)-3-iodo-6-methyl-6,7-dihydro-4H-pyrazolo[1,5-a]pyrazine-5-carboxylate(Intermediate I-1, 482 mg, 1.33 mmol) in dioxane (20 mL) was addedmethyl(2S)-1-[(2S)-2-methyl-5-oxo-pyrrolidin-3-yl]pyrrolidine-2-carboxylate(349 mg, 1.54 mmol), (1R,2R)—N1,N2-dimethylcyclohexane-1,2-diamine (39mg, 0.27 mmol), K₃PO₄ (565 mg, 2.66 mmol) and CuI (52 mg, 0.27 mmol).The reaction mixture was stirred at 110° C. for 12 h under N₂ atmosphereand then diluted by EtOAc (50 mL), filtered and the filtrate wasconcentrated and the residue was purified by prep-HPLC to give compound2d (0.25 g) as a brown solid. LCMS: (M+H⁺) 462.2

Step 4: Preparation of methyl(2S)-1-[(2S)-2-methyl-1-[(6S)-6-methyl-5-[(3,4,5-trifluorophenyl)carbamoyl]-6,7-dihydro-4H-pyrazolo[1,5-a]pyrazin-3-yl]-5-oxo-pyrrolidin-3-yl]pyrrolidine-2-carboxylate(Compound 2e)

To a solution of tert-butyl(6S)-3-[(2S)-3-[(2S)-2-methoxycarbonylpyrrolidin-1-yl]-2-methyl-5-oxo-pyrrolidin-1-yl]-6-methyl-6,7-dihydro-4H-pyrazolo[1,5-a]pyrazine-5-carboxylate(compound 2d, 250 mg, 0.54 mmol) in EtOAc (5 mL) was added HCl (10 mL,40 mmol, 4 M in EtOAc). The reaction mixture was stirred at roomtemperature for 2 h, and then concentrated to give a brown residue (220mg). The residue (150 mg) was dissolved in DMF (2 mL), to which wereadded DIPEA (128 mg, 0.95 mmol) and phenylN-(3,4,5-trifluorophenyl)carbamate (Intermediate I-3, 113 mg, 0.42mmol). The reaction mixture was stirred at room temperature for 12hours, diluted with H₂O (20 mL), and extracted 3 times with EtOAc. Thecombined organic phase was dried and concentrated to give compound 2e(249 mg, crude) as a brown solid. LCMS: (M+H⁺) 535.2

Step 5: Preparation of(2S)-1-[(2S)-2-methyl-1-[(6S)-6-methyl-5-[(3,4,5-trifluorophenyl)carbamoyl]-6,7-dihydro-4H-pyrazolo[1,5-a]pyrazin-3-yl]-5-oxo-pyrrolidin-3-yl]pyrrolidine-2-carboxylic(Example 2)

To the mixture of methyl(2S)-1-[(2S)-2-methyl-1-[(6S)-6-methyl-5-[(3,4,5-trifluorophenyl)carbamoyl]-6,7-dihydro-4H-pyrazolo[1,5-a]pyrazin-3-yl]-5-oxo-pyrrolidin-3-yl]pyrrolidine-2-carboxylate(compound 2e, 249 mg) in THF/H₂O (4 mL, v/v 3/1) was added LiOH·H₂O (49mg, 1.14 mmol), the reaction mixture was stirred at room temperature for3 hours. The reaction was acidified to pH=5, concentrated and theresidue was purified by prep-HPLC to give Example 2 (77 mg) as a whitesolid. LCMS (M+H⁺): 520.9, ¹H NMR (400 MHz, METHANOL-d₄) δ ppm 7.61 (s,1H), 7.34-7.21 (m, 2H), 5.01 (d, J=16.9 Hz, 1H), 4.97-4.90 (m, 1H),4.49-4.37 (m, 2H), 4.36-4.28 (m, 3H), 4.22-4.15 (m, 1H), 3.90-3.78 (m,1H), 3.45-3.30 (m, 1H), 3.06 (dd, J=11.2, 16.1 Hz, 1H), 2.78 (dd, J=7.7,16.1 Hz, 1H), 2.63-2.50 (m, 1H), 2.31-2.09 (m, 3H), 1.43 (d, J=6.5 Hz,3H), 1.23 (d, J=6.8 Hz, 3H).

Example 32-[Methyl-[1-[(6S)-6-methyl-5-[(3,4,5-trifluorophenyl)carbamoyl]-6,7-dihydro-4H-pyrazolo[1,5-a]pyrazin-3-yl]-5-oxo-pyrrolidin-3-yl]amino]aceticacid

Example 3 was prepared in analogy to Example 1 by using methyl2-(methylamino)acetate instead of methyl (2S)-pyrrolidine-2-carboxylate.Example 3 (10 mg) was obtained as a white solid. LCMS (M+H⁺): 480.9, ¹HNMR (400 MHz, METHANOL-d₄) δ ppm 7.70-7.65 (m, 1H), 7.30-7.20 (m, 2H),5.10-5.01 (m, 1H), 4.95-4.73 (m, 1H), 4.47 (d, J=17.1 Hz, 1H), 4.44-4.34(m, 1H), 4.32-4.00 (m, 6H), 3.10-2.85 (m, 5H), 1.30-1.15 (m, 3H)

Example 4(2R)-1-[(2S)-2-methyl-1-[(6S)-6-methyl-5-[(3,4,5-trifluorophenyl)carbamoyl]-6,7-dihydro-4H-pyrazolo[1,5-a]pyrazin-3-yl]-5-oxo-pyrrolidin-3-yl]pyrrolidine-2-carboxylicacid

Example 4 was prepared in analogy to Example 2 by using methyl(2R)-pyrrolidine-2-carboxylate instead of methyl(2S)-pyrrolidine-2-carboxylate. Example 4 (38 mg) was obtained as awhite solid. LCMS (M+H⁺): 520.9, ¹H NMR: (400 MHz, METHANOL-d₄) δ ppm7.62 (s, 1H), 7.35-7.23 (m, 2H), 5.04 (d, J=17.1 Hz, 1H), 5.00-4.85 (m,1H), 4.53-4.40 (m, 3H), 4.38-4.27 (m, 2H), 4.23-4.15 (m, 1H), 3.80-3.70(m, 1H), 3.45-3.35 (m, 1H), 3.07 (dd, J=9.5, 16.4 Hz, 1H), 2.96-2.87 (m,1H), 2.59-2.47 (m, 1H), 2.45-2.36 (m, 1H), 2.28-2.16 (m, 1H), 2.15-2.03(m, 1H), 1.37 (d, J=6.3 Hz, 3H), 1.25 (d, J=6.9 Hz, 3H)

Example 51-[1-[(6S)-6-methyl-5-[(3,4,5-trifluorophenyl)carbamoyl]-6,7-dihydro-4H-pyrazolo[1,5-a]pyrazin-3-yl]-5-oxo-pyrrolidin-3-yl]pyrrolidine-3-carboxylicacid

Example 5 was prepared in analogy to Example 1 by using methylpyrrolidine-3-carboxylate instead of methyl(2S)-pyrrolidine-2-carboxylate. Example 5 (10 mg) was obtained as awhite solid. LCMS (M+H⁺) 506.9, ¹H NMR (400 MHz, DMSO-d₆) δ ppm ¹H NMR(400 MHz, DMSO-d₆) δ=9.19 (s, 1H), 8.30 (br s, 1H), 7.61 (s, 0.5H), 7.60(s, 0.5H), 7.48-7.38 (m, 2H), 5.03-4.92 (m, 1H), 4.91-4.80 (m, 1H),4.44-4.32 (m, 1H), 4.24-4.15 (m, 1H), 4.14-4.06 (m, 1H), 3.89-3.83 (m,2H), 3.50-3.40 (m, 1H), 3.22-3.11 (m, 1H), 2.98-2.86 (m, 1H), 2.86-2.75(m, 1H), 2.70-2.50, 3H), 2.48-2.32 (m, 1H), 2.05-1.90 (m, 2H), 1.20-1.05(m, 3H).

Example 6(2S)-1-[1-[(6S,7S)-6,7-dimethyl-5-[(3,4,5-trifluorophenyl)carbamoyl]-6,7-dihydro-4H-pyrazolo[1,5-a]pyrazin-3-yl]-5-oxo-pyrrolidin-3-yl]pyrrolidine-2-carboxylicacid

The Example 6 was prepared in analogy to Example 1 by using tert-butyl(6S,7S)-3-iodo-6,7-dimethyl-6,7-dihydro-4H-pyrazolo[1,5-a]pyrazine-5-carboxylate(Intermediate I-2) instead of tert-butyl(6S)-3-iodo-6-methyl-6,7-dihydro-4H-pyrazolo[1,5-a]pyrazine-5-carboxylate(Intermediate I-1). Prep-HPLC purification afforded Example 6 as twoisomers, Example 6-1 and Example 6-2.

Example 6-1 (14 mg) was obtained as white solid. LCMS (M+H⁺): 521.2, ¹HNMR (400 MHz, METHANOL-d₄) δ ppm 7.64 (s, 1H), 7.55-7.40 (m, 2H), 5.21(d, J=17.0 Hz, 1H), 4.82 (q, J=6.8 Hz, 1H), 4.52 (d, J=17.0 Hz, 1H),4.38 (q, J=6.5 Hz, 1H), 4.31-4.15 (m, 2H), 4.03 (dd, J=4.5, 9.7 Hz, 1H),3.98-3.80 (m, 2H), 3.20 (dt, J=6.6, 10.6 Hz, 1H), 3.14-3.03 (m, 1H),2.99-2.89 (m, 1H), 2.58-2.41 (m, 1H), 2.34-2.22 (m, 1H), 2.15 (tdd,J=3.2, 6.6, 13.2 Hz, 1H), 2.05-1.94 (m, 1H), 1.43 (d, J=6.6 Hz, 3H),1.25 (d, J=6.8 Hz, 3H).

Example 6-2 (27 mg) was obtained as white solid. LCMS (M+H⁺): 521.2, ¹HNMR (400 MHz, METHANOL-d₄) δ=7.66 (s, 1H), 7.42-7.30 (m, 2H), 5.08 (d,J=16.9 Hz, 1H), 4.80 (q, J=7.2 Hz, 1H), 4.52 (d, J=16.9 Hz, 1H),4.43-4.27 (m, 2H), 4.20-4.06 (m, 2H), 3.95 (br dd, J=4.8, 9.8 Hz, 1H),3.74 (br t, J=7.0 Hz, 1H), 3.24-3.13 (m, 1H), 3.08-2.98 (m, 1H),2.92-2.83 (m, 1H), 2.54-2.41 (m, 1H), 2.32-2.22 (m, 1H), 2.12 (tdd,J=3.5, 6.6, 9.7 Hz, 1H), 2.00-1.92 (m, 1H), 1.45 (d, J=6.6 Hz, 3H), 1.24(d, J=7.0 Hz, 3H).

Example 72-[1-[(6S)-6-methyl-5-[(3,4,5-trifluorophenyl)carbamoyl]-6,7-dihydro-4H-pyrazolo[1,5-a]pyrazin-3-yl]-5-oxo-pyrrolidin-3-yl]benzoicacid

The title compound was prepared according to the following scheme:

Step 1: Preparation oftert-butyl-[(2-iodophenyl)methoxy]-dimethyl-silane (Compound 7b)

To a solution of (2-iodophenyl)methanol (compound 7a, 2.34 g, 10.0 mmol)in DCM (15 mL) was added imidazole (2.04 g, 30.0 mmol) followed byadding dropwise a solution of tert-butylchlorodimethylsilane (1.81 g,12.0 mmol) in DCM (5 mL). The resulting suspension was stirred at roomtemperature for 2 hours. The reaction mixture was concentrated. Theresidue was dissolved in PE/EA (v/v=5/1), and washed with water. Theaqueous phase was extracted with PE/EA (v/v=5/1) twice. The combinedorganic phase was concentrated, and the residue was purified by columnchromatography to give compound 7b (3.31 g). LCMS (M+H⁺): 349.

Step 2: Preparation of ethyl3-[2-[[tert-butyl(dimethyl)silyl]oxymethyl]phenyl]prop-2-enoate(Compound 7c)

To a solution of tert-butyl-[(2-iodophenyl)methoxy]-dimethyl-silane(compound 7b, 6.0 g, 17.2 mmol), ethyl acrylate (6.9 g, 7.34 mL, 68.9mmol), TEA (7.0 g, 9.6 mL, 68.9 mmol), tri-o-tolylphosphine (524 mg,1.72 mmol) in acetonitrile (20 mL) was added palladium acetate (387 mg,1.72 mmol). The reaction mixture was flushed with argon, then heated at90° C. overnight. The reaction mixture was cooled down, quenched byice-water, extracted with PE/EA (v/v=10/1) twice. The combined organicphase was concentrated. The residue was purified by columnchromatography (eluting with 5% EtOAc in petroleum ether) to givecompound 7c (5.2 g). LCMS (M+H⁺): 321.

Step 3: Preparation of ethyl3-[2-[[tert-butyl(dimethyl)silyl]oxymethyl]phenyl]-4-nitro-butanoate(Compound 7d)

To a solution of compound ethyl3-[2-[[tert-butyl(dimethyl)silyl]oxymethyl]phenyl]prop-2-enoate(compound 7c, 3.20 g, 10.0 mmol) in nitromethane (20 mL) was added1,1,3,3-tetramethylguanidine (230.0 mg, 2.0 mmol). The reaction mixturewas stirred at room temperature for 30 minutes, heated at 85° C.overnight and then concentrated. The residue was purified by columnchromatography (eluting with 5%-10% EtOAc in petroleum ether) to givecompound 7d (1.80 g). LCMS (M+H⁺): 382.

Step 4: Preparation of4-[2-[[tert-butyl(dimethyl)silyl]oxymethyl]phenyl]pyrrolidin-2-one(Compound 7e)

To a solution of ethyl3-[2-[[tert-butyl(dimethyl)silyl]oxymethyl]phenyl]-4-nitro-butanoate(compound 7d, 1.72 g, 4.5 mmol) in EtOAc (10 mL) and EtOH (10 mL) wereadded saturated aqueous ammonium chloride solution (10 mL) and zinc(2.35 g, 36.0 mmol). The reaction mixture was heated at 90° C.overnight, and then cooled down and filtrated. The filtrate wasconcentrated. The residue was treated with water, basified to pH 8.0with 2.5 M aqueous NaOH solution, and extracted with EtOAc twice. Thecombined organic phase was dried over Na₂SO₄, filtrated and concentratedto give compound 7e (1.37 g, crude), which was used directly in nextstep. LCMS (M+H⁺): 306.

Step 5: Preparation of tert-butyl(6S)-3-[4-[2-[[tert-butyl(dimethyl)silyl]oxymethyl]phenyl]-2-oxo-pyrrolidin-1-yl]-6-methyl-6,7-dihydro-4H-pyrazolo[1,5-a]pyrazine-5-carboxylate(Compound 7f)

To a solution of4-[2-[[tert-butyl(dimethyl)silyl]oxymethyl]phenyl]pyrrolidin-2-one(compound 7e, 1.0 g, 3.30 mmol) in DMSO (15 mL) were added tert-butyl(6S)-3-iodo-6-methyl-6,7-dihydro-4H-pyrazolo[1,5-a]pyrazine-5-carboxylate(Intermediate I-1, 1.2 g, 3.30 mmol), K₃PO₄ (1.4 g, 6.60 mmol),(1R,2R)—N1,N2-dimethylcyclohexane-1,2-diamine (188.0 mg, 1.32 mmol) andCuI (126.0 mg, 661 μmol). The reaction mixture was flushed withnitrogen, sealed and heated under microwave at 110° C. for 2 hours. Thereaction mixture was cooled down, quenched with ice-water and extractedwith EtOAc twice. The combined organic layer was dried over Na₂SO₄ andconcentrated. The residue was purified by column chromatography to givecompound 7f (1.4 g). LCMS (M+H⁺): 541.

Step 6: Preparation of tert-butyl(6S)-3-[4-[2-(hydroxymethyl)phenyl]-2-oxo-pyrrolidin-1-yl]-6-methyl-6,7-dihydro-4H-pyrazolo[1,5-a]pyrazine-5-carboxylate(Compound 7g)

A mixture of tert-butyl(6S)-3-[4-[2-[[tert-butyl(dimethyl)silyl]oxymethyl]phenyl]-2-oxo-pyrrolidin-1-yl]-6-methyl-6,7-dihydro-4H-pyrazolo[1,5-a]pyrazine-5-carboxylate(compound 7f, 1.41 g, 2.6 mmol) and tetrabutylammonium fluoride solution(1.0 M in THF, 3 mL) was stirred at room temperature for 2 hours. Thereaction mixture was concentrated and the residue was purified by columnchromatography to give compound 7g (1.1 g). LCMS (M+H⁺): 427.

Step 7: Preparation of2-[1-[(6S)-5-tert-butoxycarbonyl-6-methyl-6,7-dihydro-4H-pyrazolo[1,5-a]pyrazin-3-yl]-5-oxo-pyrrolidin-3-yl]benzoicacid (Compound 7h)

To a solution of tert-butyl(6S)-3-[4-[2-(hydroxymethyl)phenyl]-2-oxo-pyrrolidin-1-yl]-6-methyl-6,7-dihydro-4H-pyrazolo[1,5-a]pyrazine-5-carboxylate(compound 7g, 700.0 mg, 1.64 mmol) in acetonitrile (5 mL) and water (10mL) was added 2,2,6,6-tetramethylpiperidine-N-oxide (25.6 mg, 164 μmol)and potassium bromide (19.5 mg, 164 μmol). After 10 minutes, sodiumhypochlorite (14.5%, 2.45 mol/L, 3.35 mL, 8.20 mmol) was added dropwise.Then 2N aqueous sodium hydroxide solution was added to adjust pH=8-10.The reaction mixture was stirred at room temperature for 2 hours, andthen at 50° C. for 3 hours. Another batch of NaClO (14.5%, 3.35 mL) wasadded and the mixture was stirred at 50° C. for another 3 hours, andthen quenched with ethanol, concentrated and acidified to pH=4-5, andextracted with EtOAc twice. The organic phase was dried and concentratedto give crude compound 7h (723.0 mg, crude). LCMS (M+H⁺): 441.

Step 8: Preparation of2-[1-[(6S)-6-methyl-5-[(3,4,5-trifluorophenyl)carbamoyl]-6,7-dihydro-4H-pyrazolo[1,5-a]pyrazin-3-yl]-5-oxo-pyrrolidin-3-yl]benzoicacid (Example 7)

The mixture of2-[1-[(6S)-5-tert-butoxycarbonyl-6-methyl-6,7-dihydro-4H-pyrazolo[1,5-a]pyrazin-3-yl]-5-oxo-pyrrolidin-3-yl]benzoicacid (compound 7h, 723.0 mg, 1.64 mmol), 2,2,2-trifluoroacetic acid (5.0mL) and DCM (2.5 mL) was stirred at room temperature for 30 minutes. Thereaction mixture was concentrated, then toluene was added for azeotropicdistillation. The residue was dissolved with DCE (10 mL), to which wereadded DIPEA (2.0 mL) and phenyl N-(3,4,5-trifluorophenyl)carbamate(Intermediate I-3, 658.0 mg, 2.46 mmol). The reaction mixture was heatedat 40° C. for 3 hours and then concentrated. The residue was purified bysilica gel column chromatography and then prep-HPLC to give Example 7(460 mg). LCMS (M+H⁺): 514.2, ¹H NMR (400 MHz, METHANOL-d₄) δ ppm 7.96(d, J=7.6 Hz, 1H), 7.68-7.55 (m, 3H), 7.43-7.36 (m, 1H), 7.34-7.24 (m,2H), 5.14-5.04 (m, 1H), 5.00-4.93 (m, 1H), 4.70-4.58 (m, 1H), 4.58-4.50(m, 1H), 4.34-4.20 (m, 2H), 4.20-4.13 (m, 1H), 3.96-3.87 (m, 1H), 3.02(dd, J=9.2, 17.2 Hz, 1H), 2.77 (dd, J=7.5, 17.2 Hz, 1H), 1.29 (d, J=7.0Hz, 3H).

Example 7 could be separated to two isomers, Example 7-1 (peak 1) andExample 7-2 (peak 2), by SFC (chiral column, chiralcel® OD-H, 5 μm,20×250 mm; mobile phase, 80% CO₂ and 20% MeOH(MeOH+0.5% NH₃H₂O); flowrate 65 mL/min, back pressure 100 bar)

Example 7-1, LCMS (M+H⁺): 514.4, ¹H NMR (400 MHz, METHANOL-d4) δ ppm7.85 (d, J=7.3 Hz, 1H), 7.66 (s, 1H), 7.60-7.51 (m, 2H), 7.39-7.34 (m,1H), 7.34-7.25 (m, 2H), 5.08 (d, J=17.0 Hz, 1H), 5.03-4.95 (m, 1H),4.65-4.50 (m, 1H), 4.56 (d, J=16.9 Hz, 1H), 4.30 (dd, J=4.4, 12.8 Hz,1H), 4.26-4.19 (m, 1H), 4.16 (dd, J=1.0, 12.7 Hz, 1H), 3.93 (dd, J=6.7,9.6 Hz, 1H), 3.01 (dd, J=9.2, 17.2 Hz, 1H), 2.79 (dd, J=7.7, 17.1 Hz,1H), 1.28 (d, J=6.8 Hz, 3H)

Example 7-2, LCMS (M+H⁺): 514.4, ¹H NMR (400 MHz, METHANOL-d4) 6=7.91(d, J=7.7 Hz, 1H), 7.66 (s, 1H), 7.61-7.53 (m, 2H), 7.41-7.35 (m, 1H),7.34-7.25 (m, 2H), 5.09 (d, J=16.9 Hz, 1H), 5.00-4.94 (m, 1H), 4.65-4.57(m, 1H), 4.54 (d, J=17.0 Hz, 1H), 4.36-4.23 (m, 2H), 4.19-4.13 (m, 1H),3.90 (dd, J=6.4, 9.6 Hz, 1H), 3.02 (dd, J=9.2, 17.1 Hz, 1H), 2.79 (dd,J=7.5, 17.1 Hz, 1H), 1.28 (d, J=6.8 Hz, 3H).

Example 83-[1-[(6S)-6-methyl-5-[(3,4,5-trifluorophenyl)carbamoyl]-6,7-dihydro-4H-pyrazolo[1,5-a]pyrazin-3-yl]-5-oxo-pyrrolidin-3-yl]benzoicacid

The title compound was prepared according to the following scheme:

Preparation of tert-butyl(6S)-3-[4-(3-methoxycarbonylphenyl)-2-oxo-pyrrolidin-1-yl]-6-methyl-6,7-dihydro-4H-pyrazolo[1,5-a]pyrazine-5-carboxylate(Compound 8e)

Compound 8e was prepared in analogy to compound 7f by using methyl3-iodobenzoate (compound 8a) instead oftert-butyl-[(2-iodophenyl)methoxy]-dimethyl-silane (compound 7b).Compound 8e was obtained as a solid (263 mg). LCMS (M+H⁺): 455.

Preparation of methyl3-[1-[(6S)-6-methyl-5-[(3,4,5-trifluorophenyl)carbamoyl]-6,7-dihydro-4H-pyrazolo[1,5-a]pyrazin-3-yl]-5-oxo-pyrrolidin-3-yl]benzoate(Compound 8f)

A mixture of tert-butyl(6S)-3-[4-(3-methoxycarbonylphenyl)-2-oxo-pyrrolidin-1-yl]-6-methyl-6,7-dihydro-4H-pyrazolo[1,5-a]pyrazine-5-carboxylate(compound 8e, 260.0 mg, 572 mol), 2,2,2-trifluoroacetic acid (2 mL) andDCM (1 mL) was stirred at room temperature for 30 minutes. The reactionmixture was concentrated, then toluene was added for azeotropicdistillation. The residue was dissolved in DCM (3 mL), to which werethen added DIPEA (1.0 mL) and phenyl N-(3,4,5-trifluorophenyl)carbamate(Intermediate I-3, 229 mg, 858 μmol). The reaction mixture was heated at40° C. for 3 hours and then concentrated. The residue was purified bycolumn chromatography (eluting with 50%-60% EtOAc (containing 10% MeOH)in petroleum ether) to afford compound 8f (287 mg). LCMS (M+H⁺): 528.

Preparation of3-[1-[(6S)-6-methyl-5-[(3,4,5-trifluorophenyl)carbamoyl]-6,7-dihydro-4H-pyrazolo[1,5-a]pyrazin-3-yl]-5-oxo-pyrrolidin-3-yl]benzoicacid (Example 8)

To a solution of methyl3-[1-[(6S)-6-methyl-5-[(3,4,5-trifluorophenyl)carbamoyl]-6,7-dihydro-4H-pyrazolo[1,5-a]pyrazin-3-yl]-5-oxo-pyrrolidin-3-yl]benzoate(compound 8f, 260 mg, 493 μmol) in THF (1.3 mL) was added lithiumhydroxide aqueous solution (2 M, 1.3 mL, 2.6 mmol). The reaction mixturewas stirred at room temperature for 2 hours, acidified to pH=4-5, andconcentrated. The residue was purified by prep-HPLC to give Example 8(120 mg). LCMS (M+H⁺): 514. ¹H NMR (400 MHz, METHANOL-d₄) δ=8.11-8.04(m, 1H), 8.00-7.94 (m, 1H), 7.72-7.63 (m, 2H), 7.55-7.49 (m, 1H),7.33-7.25 (m, 2H), 5.16-5.06 (m, 1H), 5.03-4.94 (m, 1H), 4.63-4.52 (m,1H), 4.35-4.15 (m, 3H), 3.99-3.89 (m, 2H), 3.08-2.98 (m, 1H), 2.82-2.71(m, 1H), 1.33-1.24 (m, 3H).

Example 9(2R)-1-[1-[(6S)-6-methyl-5-[(3,4,5-trifluorophenyl)carbamoyl]-6,7-dihydro-4H-pyrazolo[1,5-a]pyrazin-3-yl]-5-oxo-pyrrolidin-3-yl]pyrrolidine-2-carboxylicacid

Example 9 was prepared in analogy to Example 1 by using methyl(2R)-pyrrolidine-2-carboxylate instead of methyl(2S)-pyrrolidine-2-carboxylate. Example 9 (54 mg) was obtained as awhite solid. LCMS (M+H+) 507.3, ¹H NMR (400 MHz, METHANOL-d4) δ ppm7.71-7.62 (m, 1H), 7.39-7.25 (m, 2H), 5.13-5.02 (m, 1H), 5.00-4.85 (m,1H), 4.53-3.98 (m, 7H), 3.88-3.76 (m, 1H), 3.39-3.34 (m, 1H), 3.14-3.05(m, 1H), 2.98-2.85 (m, 1H), 2.65-2.49 (m, 1H), 2.40-2.27 (m, 1H),2.26-2.15 (m, 1H), 2.11-1.93 (m, 1H), 1.30-1.20 (m, 3H)

Example 103-Fluoro-2-[1-[(6S)-6-methyl-5-[(3,4,5-trifluorophenyl)carbamoyl]-6,7-dihydro-4H-pyrazolo[1,5-a]pyrazin-3-yl]-5-oxo-pyrrolidin-3-yl]benzoicacid

Example 10 was prepared in analogy to Example 7 by using(2-bromo-3-fluoro-phenyl)methanol instead of (2-iodophenyl)methanol.Separation of the final product by SFC gave Example 10 as two isomers,Example 10-1 and Example 10-2. SFC conditions: chiral column, chiralcel®OZ-H, 5 μm, 20×250 mm; mobile phase, 80% CO₂ and 20% MeOH (MeOH+0.5%NH₃H₂O); flow rate, 65 mL/min, back pressure 100 bar.

Example 10-1 was obtained (12 mg) as a white solid. LCMS (M+H)⁺: 532.2,¹H NMR (400 MHz, METHANOL-d₄) δ ppm 7.55 (s, 1H), 7.39 (d, J=7.0 Hz,1H), 7.29-7.06 (m, 4H), 4.97 (d, J=16.9 Hz, 1H), 4.93-4.84 (m, 1H),4.49-4.42 (m, 2H), 4.24-4.14 (m, 1H), 4.10-4.00 (m, 2H), 3.97-3.86 (m,1H), 2.88-2.72 (m, 2H), 1.17 (d, J=6.8 Hz, 3H).

Example 10-2 was obtained (8 mg) as a white solid. LCMS (M+H)⁺: 532.2,¹H NMR (400 MHz, METHANOL-d₄) δ ppm 7.67 (s, 1H), 7.57 (d, J=7.6 Hz,1H), 7.45-7.20 (m, 4H), 5.14 (d, J=17.1 Hz, 1H), 5.03-4.95 (m, 1H), 4.64(br d, J=8.2 Hz, 1H), 4.55 (d, J=17.0 Hz, 1H), 4.31 (dd, J=4.5, 12.5 Hz,1H), 4.25-4.13 (m, 2H), 4.03-3.96 (m, 1H), 3.01-2.85 (m, 2H), 1.29 (d,J=7.0 Hz, 3H).

Example 112-Fluoro-6-[1-[(6S)-6-methyl-5-[(3,4,5-trifluorophenyl)carbamoyl]-6,7-dihydro-4H-pyrazolo[1,5-a]pyrazin-3-yl]-5-oxo-pyrrolidin-3-yl]benzoicacid

Example 11 was prepared in analogy to Example 7 by using(2-bromo-6-fluoro-phenyl)methanol instead of (2-iodophenyl)methanol.Separation of the final product by SFC gave Example 11 as two isomers,Example 11-1 and Example 11-2. SFC conditions: chiral column, chiralcel®OZ-H, 5 μm, 20×250 mm; mobile phase, 80% CO₂ and 20% MeOH (MeOH+0.5%NH₃H₂O); flow rate, 65 mL/min, back pressure 100 bar.

Example 11-1 was obtained (22 mg) as a white solid. LCMS (M+H)⁺: 532.2,¹H NMR (400 MHz, METHANOL-d₄) δ ppm 7.55 (s, 1H), 7.39-7.29 (m, 1H),7.26-7.14 (m, 3H), 6.97 (t, J=8.7 Hz, 1H), 4.95 (d, J=16.9 Hz, 1H),4.91-4.83 (m, 1H), 4.46 (d, J=16.9 Hz, 1H), 4.26-4.14 (m, 1H), 4.12-4.01(m, 2H), 3.99-3.81 (m, 2H), 2.93-2.80 (m, 1H), 2.76-2.65 (m, 1H), 1.16(d, J=6.8 Hz, 3H).

Example 11-2 was obtained (22 mg) as a white solid. LCMS (M+H)⁺: 532.2,¹H NMR (400 MHz, METHANOL-d₄) δ ppm 7.66 (s, 1H), 7.47-7.26 (m, 4H),7.08 (t, J=8.4 Hz, 1H), 5.16 (d, J=16.9 Hz, 1H), 5.05-4.96 (m, 1H), 4.53(d, J=16.9 Hz, 1H), 4.34-4.12 (m, 3H), 4.11-3.90 (m, 2H), 3.04-2.93 (m,1H), 2.93-2.81 (m, 1H), 1.28 (d, J=6.8 Hz, 3H).

Example 122-[[1-[(6S)-6-methyl-5-[(3,4,5-trifluorophenyl)carbamoyl]-6,7-dihydro-4H-pyrazolo[1,5-a]pyrazin-3-yl]-5-oxo-pyrrolidin-3-yl]amino]benzoicacid

The title compound was prepared according to the following scheme:

Step 1: Preparation of methyl 2-[(5-oxopyrrolidin-3-yl)amino]benzoate(Compound 12a)

A mixture of pyrrolidine-2,4-dione (300 mg, 3.03 mmol) and methyl2-aminobenzoate (0.43 mL, 3.33 mmol), AcOH (182 mg, 3.03 mmol) in DCE(10 mL) was stirred at 50° C. for 16 hours. The reaction mixture wasconcentrated to give a yellow solid. The solid was dissolved in methanol(10 mL), to which were added Pd/C (69 mg, 0.3 mmol). The resultingmixture was stirred under H₂ (50 psi) for 16 hours at room temperature,and then filtered. The filtrate was concentrated, and the residue waspurified by prep-TLC (PE:EtOAc=1:1) to give compound 12a (170 mg) as acolorless oil. LCMS (M+H⁺) 235.0

Step 2: Preparation of tert-butyl(6S)-3-[4-(2-methoxycarbonylanilino)-2-oxo-pyrrolidin-1-yl]-6-methyl-6,7-dihydro-4H-pyrazolo[1,5-a]pyrazine-5-carboxylate(Compound 12b)

A mixture of methyl 2-[(5-oxopyrrolidin-3-yl)amino]benzoate (compound12a, 170 mg, 0.73 mmol), tert-butyl (6S)-3-iodo-6-methyl-6,7-dihydro-4H-pyrazolo[1,5-a]pyrazine-5-carboxylate(Intermediate I-1, 290 mg, 0.8 mmol),(1R,2R)—N1,N2-dimethylcyclohexane-1,2-diamine (21 mg, 0.15 mmol), CuI(28 mg, 0.15 mmol) and K₃PO₄ (308 mg) in 1,4-dioxane (15 mL) was stirredat 110° C. under N₂ for 32 hours. The reaction mixture was filtered, andthe filtrate was concentrated. The residue was purified by prep-TLC(PE:EtOAc, v/v=1/3) to give compound 12b (30 mg) as a yellow oil. LCMS(M+H⁺) 470.2

Step 3: Preparation of2-[[1-[(6S)-6-methyl-4,5,6,7-tetrahydropyrazolo[1,5-a]pyrazin-3-yl]-5-oxo-pyrrolidin-3-yl]amino]benzoicacid (Compound 12c)

To a solution of tert-butyl(6S)-3-[4-(2-methoxycarbonylanilino)-2-oxo-pyrrolidin-1-yl]-6-methyl-6,7-dihydro-4H-pyrazolo[1,5-a]pyrazine-5-carboxylate(compound 12b, 30 mg) in THF (2 mL), methanol (2 mL) and water (2 mL)was added LiOH (6 mg). The reaction mixture was stirred at roomtemperature for 2 hours and then concentrated. The obtained residue wasdissolved in EtOAc (2 mL), to which was added a solution of HCl in EtOAc(4 M, 0.08 mL). The reaction mixture was stirred at room temperature for2 hours, and concentrated to give crude compound 12c (21 mg) as a whitesolid. LCMS (M+H⁺) 356.1

Step 4: Preparation of2-[[1-[(6S)-6-methyl-5-[(3,4,5-trifluorophenyl)carbamoyl]-6,7-dihydro-4H-pyrazolo[1,5-a]pyrazin-3-yl]-5-oxo-pyrrolidin-3-yl]amino]benzoicacid (Example 12)

A mixture of2-[[1-[(6S)-6-methyl-4,5,6,7-tetrahydropyrazolo[1,5-a]pyrazin-3-yl]-5-oxo-pyrrolidin-3-yl]amino]benzoicacid (compound 12c, 21 mg) and phenyl N-(3,4,5-trifluorophenyl)carbamate(18 mg) and triethylamine (0.02 mL) in DCM (3 mL) was stirred at roomtemperature for 3 hours. The reaction mixture was concentrated, and theresidue was purified by prep-HPLC to give Example 12 as a yellow oil.LCMS (M+H⁺) 529.1, ¹H NMR (400 MHz, DMSO-d₆) δ ppm 7.90-7.80 (m, 1H),7.80-7.65 (m, 1H), 7.60-7.50 (m, 1H), 7.35-7.20 (m, 1H), 6.80-6.70 (m,1H), 6.65-6.52 (m, 1H), 5.25-5.00 (m, 1H), 4.95-4.85 (m, 1H), 4.49-4.29(m, 2H), 4.28-4.01 (m, 3H), 3.70-3.50 (m, 1H), 3.07-2.87 (m, 1H),2.39-2.23 (m, 1H), 1.20-1.10 (m, 3H)

Example 132-[7-[(6S)-6-methyl-5-[(3,4,5-trifluorophenyl)carbamoyl]-6,7-dihydro-4H-pyrazolo[1,5-a]pyrazin-3-yl]-6-oxo-3-oxa-7,9-diazabicyclo[3.3.1]nonan-9-yl]aceticacid

The title compound was prepared according to the following scheme:

Preparation of 09-benzyl 07-tert-butyl6-oxo-3-oxa-7,9-diazabicyclo[3.3.1]nonane-7,9-dicarboxylate (Compound13a)

To a solution tert-butyl3-oxa-7,9-diazabicyclo[3.3.1]nonane-7-carboxylate (400 mg, 1.75 mmol)and Et₃N (0.49 mL, 3.5 mmol) in DCM (10 mL) was added CbzCl (448 mg,2.63 mmol) at room temperature. The reaction mixture was stirred at roomtemperature for 2 hours and then water (10.0 mL) was added, and themixture is extracted three times with EtOAc (30 mL each). The combinedorganic phase was dried over Na₂SO₄ and concentrated. The residue waspurified by silica gel column chromatography (PE:EtOAc, from 10:1 to2:1) to give a white solid (300 mg). The solid was dissolved in ACN (8mL) and water (2 mL), to which were added RuCl₃ (35 mg, 0.170 mmol) andNaIO₄ (532 mg, 2.48 mmol). The reaction mixture was stirred at roomtemperature for 36 hours and water (10 mL) was added, and the mixturewas extracted three times with EtOAc (20 mL). The combined organic phasewas dried over Na₂SO₄ and concentrated. The residue was purified bycolumn (PE:EtOAc, from 10:1 to 1:1) to give the desired product 13a as ayellow oil (150 mg). LCMS (M−100+H⁺) 277.1

Preparation of benzyl7-[(6S)-5-tert-butoxycarbonyl-6-methyl-6,7-dihydro-4H-pyrazolo[1,5-a]pyrazin-3-yl]-6-oxo-3-oxa-7,9-diazabicyclo[3.3.1]nonane-9-carboxylate(Compound 13b)

To a solution of 09-benzyl 07-tert-butyl6-oxo-3-oxa-7,9-diazabicyclo[3.3.1]nonane-7,9-dicarboxylate (compound13a, 150 mg, 0.400 mmol) in EtOAc (5 mL) was added a solution of HCl inEtOAc (4 M, 10 mL). The mixture was stirred at room temperature for 2hours, and concentrated. The crude material was dissolved in 1,4-dioxane(10 mL), to which were tert-butyl(6S)-3-iodo-6-methyl-6,7-dihydro-4H-pyrazolo[1,5-a]pyrazine-5-carboxylate(Intermediate I-1, 158 mg, 0.430 mmol) and K₃PO₄ (154 mg, 0.720 mmol),CuI (14 mg, 0.070 mmol), (1R,2R)—N1,N2-dimethylcyclohexane-1,2-diamine(11 mg, 0.070 mmol) under N₂. The resulting mixture was stirred at roomtemperature for 14 hours. After cooled down, the reaction mixture wasfiltered, and concentrated under the reduced pressure. The residue waspurified by silica gel column chromatography (PE:EtOAc from 10:1 to 1:1)to give the compound 13b (80 mg) as a yellow oil. LCMS (M+H⁺) 512.2

Preparation of tert-butyl(6S)-3-[9-(2-ethoxy-2-oxo-ethyl)-6-oxo-3-oxa-7,9-diazabicyclo[3.3.1]nonan-7-yl]-6-methyl-6,7-dihydro-4H-pyrazolo[1,5-a]pyrazine-5-carboxylate(Compound 13c)

A mixture of benzyl7-[(6S)-5-tert-butoxycarbonyl-6-methyl-6,7-dihydro-4H-pyrazolo[1,5-a]pyrazin-3-yl]-6-oxo-3-oxa-7,9-diazabicyclo[3.3.1]nonane-9-carboxylate(compound 13b, 40 mg, 0.080 mmol) and Pd/C (2 mg, 0.020 mmol) in MeOH (5mL) was stirred under H₂ at room temperature for 14 hours. The reactionmixture was filtered and concentrated. The residue was purified byprep-TLC (DCM:MeOH=10:1) to give tert-butyl(6S)-6-methyl-3-(6-oxo-3-oxa-7,9-diazabicyclo[3.3.1]nonan-7-yl)-6,7-dihydro-4H-pyrazolo[1,5-a]pyrazine-5-carboxylateas a colorless oil (18 mg). This compound was dissolved in ACN (10 mL),to which were added K₂CO₃ (14 mg, 0.10 mmol) and ethyl 2-bromoacetate(0.01 mL, 0.070 mmol, 1.5 eq). The reaction mixture was stirred at roomtemperature for 14 hours, and then concentrated to give crude compound13c as a yellow oil (18 mg). LCMS (M+H⁺) 464.1

Preparation of2-[7-[(6S)-6-methyl-4,5,6,7-tetrahydropyrazolo[1,5-a]pyrazin-3-yl]-6-oxo-3-oxa-7,9-diazabicyclo[3.3.1]nonan-9-yl]aceticacid (Compound 13d)

To a mixture of tert-butyl(6S)-3-[9-(2-ethoxy-2-oxo-ethyl)-6-oxo-3-oxa-7,9-diazabicyclo[3.3.1]nonan-7-yl]-6-methyl-6,7-dihydro-4H-pyrazolo[1,5-a]pyrazine-5-carboxylate(compound 13c, 18 mg, 0.04 mmol) of water (1 mL), methanol (1 mL) andTHF (1 mL) was added LiOH (4 mg, 0.08 mmol) at room temperature. Thereaction mixture was stirred at room temperature for 2 hours, and thenconcentrated. The residue was purified by prep-TLC (DCM:MeOH=10:1) to2-[7-[(6S)-5-tert-butoxycarbonyl-6-methyl-6,7-dihydro-4H-pyrazolo[1,5-a]pyrazin-3-yl]-6-oxo-3-oxa-7,9-diazabicyclo[3.3.1]nonan-9-yl]aceticacid as a yellow oil (12 mg). This acid was dissolved in EtOAc (5 mL),to which was added a solution of HCl in EtOAc (10 mL, 0.03 mmol). Thereaction mixture was stirred at room temperature for 2 hours, andconcentrated to give crude compound 13d (11 mg) as a yellow oil.

Preparation of2-[7-[(6S)-6-methyl-5-[(3,4,5-trifluorophenyl)carbamoyl]-6,7-dihydro-4H-pyrazolo[1,5-a]pyrazin-3-yl]-6-oxo-3-oxa-7,9-diazabicyclo[3.3.1]nonan-9-yl]aceticacid (Example 13)

To a mixture of2-[7-[(6S)-6-methyl-4,5,6,7-tetrahydropyrazolo[1,5-a]pyrazin-3-yl]-6-oxo-3-oxa-7,9-diazabicyclo[3.3.1]nonan-9-yl]aceticacid (compound 13d, 11 mg, 0.03 mmol) and DIPEA (0.01 mL, 0.070 mmol) inDMF (2 mL) was added phenyl N-(3,4,5-trifluorophenyl)carbamate(Intermediate I-3, 11 mg, 0.04 mmol). The reaction mixture was stirredat room temperature for 16 hours, and then concentrated. The residue waspurified by HPLC to give Example 13 (3.5 mg) as a white solid. LCMS(M+H⁺) 509.1; ¹H NMR (400 MHz, DMSO-d6) δ ppm 9.30-9.20 (m, 1H), 7.66(s, 0.5H), 7.65 (s, 0.5H), 7.50-7.38 (m, 1H), 4.91-4.73 (m, 2H), 4.43(s, 1H), 4.32 (m, 1H), 4.27-4.12 (m, 3H), 4.07-3.85 (m, 3H), 3.78-3.62(m, 5H), 1.20-1.10 (m, 3H)

Example 144-Fluoro-2-[1-[(6S)-6-methyl-5-[(3,4,5-trifluorophenyl)carbamoyl]-6,7-dihydro-4H-pyrazolo[1,5-a]pyrazin-3-yl]-5-oxo-pyrrolidin-3-yl]benzoicacid

The title compound was prepared according to the following scheme:

Step 1: Preparation of methyl4-fluoro-2-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)benzoate(Compound 14b)

A mixture of methyl 2-bromo-4-fluorobenzoate (compound 14a, 1 g, 4.29mmol), 4,4,4′,4′,5,5,5′,5′-octamethyl-2,2′-bi(1,3,2-dioxaborolane) (1.63g, 6.44 mmol), PdCl₂(DPPF) (350 mg, 429 μmol) and potassium acetate (632mg, 6.44 mmol) in dioxane (30 mL) was heated to 90° C. and stirred for 2hours under nitrogen. The crude reaction mixture was concentrated invacuo. The residue was purified by flash chromatography (silica gel, 40g, 0% to 10% EtOAc in petroleum ether) to give compound 14b as colorlessoil (1 g), LCMS (M+H⁺): 281.

Step 2: Preparation of methyl4-fluoro-2-(5-oxo-1,2-dihydropyrrol-3-yl)benzoate (Compound 14c)

A mixture of methyl4-fluoro-2-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)benzoate(compound 14b, 951 mg, 3.4 mmol), tert-butyl2-oxo-4-(tosyloxy)-2,5-dihydro-1H-pyrrole-1-carboxylate (0.8 g, 2.26mmol, see J. Org. Chem. 2002, 67, 4702 for its synthesis), PdCl₂(DPPF)(162 mg, 226 μmol) and K₂CO₃ (626 mg, 4.53 mmol) in dioxane/H₂O (10:1)(20 mL) was heated to 90° C. and stirred for 2 hours under nitrogen. Thereaction mixture was filtered through celite. The filtrate wasconcentrated in vacuo. The residue was purified by flash chromatography(silica gel, 40 g, 0% to 100% EtOAc in petroleum ether, EtOAc contain10% MeOH) to give compound 14c (150 mg) as light yellow oil. LCMS(M+H⁺): 236.

Step 3: Preparation of methyl 4-fluoro-2-(5-oxopyrrolidin-3-yl)benzoate(Compound 14d)

A mixture of methyl4-fluoro-2-(5-oxo-2,5-dihydro-1H-pyrrol-3-yl)benzoate (compound 14c, 100mg, 425 μmol) and Pd—C (50 mg) in MeOH (20 mL) was heated to 55° C. andstirred for 20 hours under hydrogen balloon. The reaction mixture wasfiltered through celite and the filtrate was concentrated to givecompound 14d as white solid (40 mg). LCMS (M+H⁺): 238.

Step 4: Preparation of tert-butyl(6S)-3-[4-(5-fluoro-2-methoxycarbonyl-phenyl)-2-oxo-pyrrolidin-1-yl]-6-methyl-6,7-dihydro-4H-pyrazolo[1,5-a]pyrazine-5-carboxylate(Compound 14e)

To a 10 mL microwave vial was added (S)-tert-butyl3-iodo-6-methyl-6,7-dihydropyrazolo[1,5-a]pyrazine-5(4H)-carboxylate(intermediate I-1, 100 mg, 275 μmol),(1R,2R)—N1,N2-dimethylcyclohexane-1,2-diamine (15.7 mg, 110 μmol),methyl 4-fluoro-2-(5-oxopyrrolidin-3-yl)benzoate (compound 14d, 40 mg,169 μmol), copper (I) iodide (10.5 mg, 55.1 μmol) and potassiumphosphate (117 mg, 551 μmol) in DMSO (5 mL). The vial was capped and thereaction mixture was heated in the microwave at 120° C. and stirred for4 hours. After cooled down to room temperature, the reaction mixture waspoured into 20 mL of EtOAc and washed with H₂O (20 mL) and brine (20mL). The organic layer was dried over Na₂SO₄ and concentrated in vacuo.The crude product was purified by flash chromatography (silica gel, 12g, 0% to 100% EtOAc in petroleum ether, EtOAc contain 10% MeOH) to givecompound 14e as light yellow oil (40 mg). LCMS (M+H⁺): 473.

Step 5: Preparation of methyl4-fluoro-2-[1-[(6S)-6-methyl-5-[(3,4,5-trifluorophenyl)carbamoyl]-6,7-dihydro-4H-pyrazolo[1,5-a]pyrazin-3-yl]-5-oxo-pyrrolidin-3-yl]benzoate(Compound 14f)

A mixture of (6S)-tert-butyl3-(4-(5-fluoro-2-(methoxycarbonyl)phenyl)-2-oxopyrrolidin-1-yl)-6-methyl-6,7-dihydropyrazolo[1,5-a]pyrazine-5(4H)-carboxylate(compound 14e, 40 mg, 84.7 mol) in DCM/TFA (1:1, 4 mL) was stirred at20° C. for 1 hour. The reaction mixture was concentrated and the residuewas dissolved in DMF (2 mL), then addedN-ethyl-N-isopropylpropan-2-amine (109 mg, 847 μmol), and phenyl(3,4,5-trifluorophenyl)carbamate (intermediate I-3, 33.9 mg, 127 μmol).The reaction mixture was stirred at 70° C. for 1 hour. Then the reactionmixture was diluted with EtOAc, washed with water and brine. The organiclayer was concentrated to give compound 14f as light yellow oil (40 mg).LCMS (M+H⁺): 546.

Step 6: Preparation of4-fluoro-2-[1-[(6S)-6-methyl-5-[(3,4,5-trifluorophenyl)carbamoyl]-6,7-dihydro-4H-pyrazol[1,5-a]pyrazin-3-yl]-5-oxo-pyrrolidin-3-yl]benzoicacid (Example 14)

A mixture of methyl4-fluoro-2-[1-[(6S)-6-methyl-5-[(3,4,5-trifluorophenyl)carbamoyl]-6,7-dihydro-4H-pyrazolo[1,5-a]pyrazin-3-yl]-5-oxo-pyrrolidin-3-yl]benzoate(compound 14f, 30 mg, 55 μmol) and NaOH (550 μl, 1 M) in MeOH (5 mL) wasstirred at 20° C. for 1 hour, then the mixture was adjust to PH=6, thenthe solution was purified by Prep-HPLC to give Example 14 (4 mg) aswhite solid. LCMS (M+H⁺): 532.2, ¹H NMR (400 MHz, METHANOL-d₄) δ ppm7.86-7.82 (m, 1H), 7.54 (s, 1H), 7.29-7.10 (m, 3H), 7.02-6.99 (m, 1H),4.97 (dd, J=7.0, 16.9 Hz, 1H), 4.91-4.83 (m, 1H), 4.65-4.48 (m, 1H),4.43 (dd, J=5.9, 16.9 Hz, 1H), 4.27-3.95 (m, 3H), 3.82-3.78 (m, 1H),2.92-2.85 (m, 1H), 2.70-2.63 (m, 1H), 1.17 (d, J=6.8 Hz, 1.5H), 1.15 (d,J=6.8 Hz, 1.5H).

Example 155-Fluoro-2-[1-[(6S)-6-methyl-5-[(3,4,5-trifluorophenyl)carbamoyl]-6,7-dihydro-4H-pyrazolo[1,5-a]pyrazin-3-yl]-5-oxo-pyrrolidin-3-yl]benzoicacid

Example 15 was prepared in analogy to Example 14 by using methyl2-bromo-5-fluorobenzoate instead of methyl 2-bromo-4-fluorobenzoate(compound 14a). Example 15 (7 mg) was obtained as white solid. LCMS(M+H⁺): 532.2. ¹H NMR (400 MHz, METHANOL-d₄) δ ppm 7.53 (d, J=0.9 Hz,1H), 7.51-7.41 (m, 2H), 7.26-7.09 (m, 3H), 4.96 (dd, J=7.4, 16.9 Hz,1H), 4.89-4.81 (m, 1H), 4.54-4.37 (m, 2H), 4.23-3.99 (m, 3H), 3.82-3.74(m, 1H), 2.91-2.85 (m, 1H), 2.68-2.64 (m, 1H), 1.17 (d, J=6.8 Hz, 1.5H),1.15 (d, J=6.8 Hz, 1.5H).

Example 164-[1-[(6S)-6-methyl-5-[(3,4,5-trifluorophenyl)carbamoyl]-6,7-dihydro-4-pyrazol[1,5-a]pyrazin-3-yl]-5-oxo-pyrrolidin-3-yl]benzoicacid

Example 16 was prepared in analogy to Example 8 by using methyl4-iodobenzoate instead of methyl 3-iodobenzoate (compound 8a). Example16 (120 mg) was obtained as a white solid. LCMS (M+H⁺): 514.4, ¹H NMR(400 MHz, METHANOL-d₄) δ ppm 8.07-8.03 (m, 2H), 7.68 (s, 1H), 7.55-7.50(m, 2H), 7.33-7.25 (m, 2H), 5.14-5.03 (m, 1H), 5.01-4.91 (m, 1H),4.61-4.49 (m, 1H), 4.34-4.15 (m, 3H), 4.00-3.91 (m, 2H), 3.06-2.97 (m,1H), 2.84-2.75 (m, 1H), 1.29 (t, J=7.3 Hz, 3H).

Example 176-[1-[(6S)-6-methyl-5-[(3,4,5-trifluorophenyl)carbamoyl]-6,7-dihydro-4H-pyrazolo[1,5-a]pyrazin-3-yl]-5-oxo-pyrrolidin-3-yl]pyridine-2-carboxylicacid

Example 17 was prepared in analogy to Example 8 by using ethyl6-bromopyridine-2-carboxylate instead of methyl 3-iodobenzoate (compound8a). Example 17 (100 mg) was obtained as a white solid. LCMS (M+H⁺):515.2, ¹H NMR (400 MHz, METHANOL-d₄) δ ppm 8.09 (d, J=7.2 Hz, 1H), 7.99(t, J=7.7 Hz, 1H), 7.69 (s, 1H), 7.65 (d, J=7.4 Hz, 1H), 7.34-7.26 (m,2H), 5.16-5.04 (m, 1H), 5.03-4.94 (m, 1H), 4.59 (t, J=16.4 Hz, 1H),4.34-4.27 (m, 1H), 4.26-4.06 (m, 4H), 3.07-2.95 (m, 2H), 1.28 (d, J=7.0Hz, 3H).

Example 182-[1-[(6S)-6-methyl-5-[(3,4,5-trifluorophenyl)carbamoyl]-6,7-dihydro-4H-pyrazolo[1,5-a]pyrazin-3-yl]-5-oxo-pyrrolidin-3-yl]pyridine-3-carboxylicacid

Example 18 was prepared in analogy to Example 8 by using tert-butyl2-bromopyridine-3-carboxylate instead of methyl 3-iodobenzoate (compound8a). Example 18 (11 mg) was obtained as a white solid. LCMS (M+H⁺):515.5, ¹H NMR (400 MHz, METHANOL-d₄) δ ppm 8.78-8.73 (m, 1H), 8.36-8.32(m, 1H), 7.63 (s, 1H), 7.45-7.39 (m, 1H), 7.34-7.25 (m, 2H), 5.15-5.03(m, 1H), 5.01-4.93 (m, 1H), 4.86-4.81 (m, 1H), 4.53 (d, J=16.9 Hz, 1H),4.34-4.23 (m, 2H), 4.20-4.13 (m, 1H), 4.10-3.99 (m, 1H), 3.04-2.96 (m,2H), 1.32-1.24 (m, 3H).

Example 19: HBV Inhibition Assays Cell Line and Culture Conditions:

HepG2.2.15 is a stably-transfected cell line containing the HBV genome.It is derived from the hepatoblastoma cell line Hep G2 (American TypeCulture Collection, ATCC® HB-8065™) by the published proceduresdescribed in reference: MA Selles et al. Proc. Natl. Acad. Sci. USA1987, 84, 1005-1009. The cell line was maintained in Dulbecco's modifiedEagle's medium and nutrient mixture F-12 (DMEM/F-12, Gibco, Cat. #:11320-033) supplemented with 10% fetal bovine serum (Gibco, Cat.#:10099-141), 100 U/mL penicillin, 100 μg/mL streptomycin (Gibco, Cat.#:15140-122), and 0.3 mg/mL of G418 Sulfate (Gibco, Cat. #: 10131-027).

Anti-HBV Activity In Vitro:

HepG2.2.15 cells were seeded into 96-well plates at a density of 3×10⁴cells per well in culture media of 100 μL DMEM/F-12 supplemented with2.5% fetal bovine serum, 100 U/mL penicillin, 100 μg/mL streptomycin andcultured overnight at 37° C. The test compounds were serially half-logdiluted in DMSO, then diluted 100 times in culture media. 100 μL culturemedia containing diluted compounds were added into the plates to reach0.5% final concentration of DMSO in every well. Five days after compoundtreatment, culture supernatant was collected for further analysis.

For quantitative PCR detection of extracellular HBV DNA, culturesupernatant was processed by 500 μg/mL Proteinase K (Sigma, Cat.#:P2308) digestion at 50° C. for 1 hour. After heat inactivation of theenzyme at 95° C. for 15 minutes, the samples were subjected to HBV DNAquantification by qPCR. The effective compound concentration at whichHBV replication was inhibited by 50% (EC₅₀) was determined.

The Examples of the present invention were tested in the above assays asdescribed herein and found to have EC₅₀<0.5 μM in HepG2.2.15 assay asshown in Table 1 below.

TABLE 1 Activity of compounds of this invention in HepG2.2.15 assayExample No. EC₅₀ (μM)  1 0.126  2 0.098  3 0.139  4 0.105  5 0.240  6-10.112  6-2 0.099  7 0.022  7-1 0.034  7-2 0.014  8 0.089  9 0.124 10-10.106 10-2 0.017 11-1 0.312 11-2 0.077 12 0.288 13 0.099 14 0.030 150.057 16 0.228 18 0.102

1. A compound of formula (I),

wherein: R¹ is oxooxadiazabicyclo[3.3.1]nonanyl substituted bycarboxyC₁₋₆alkyl; or oxopyrrolidinyl, said oxopyrrolidinyl being oncesubstituted by carboxyC₁₋₆alkyl(C₁₋₆alkyl)amino, carboxyphenyl,carboxypyridinyl, carboxyphenylamino, halocarboxyphenyl orcarboxypyrrolidinyl; or twice substituted by carboxypyrrolidinyl andC₁₋₆alkyl; R² is H or C₁₋₆alkyl; R³ is C₁₋₆alkyl; R⁴ is phenyl, saidphenyl being three times substituted by halogen; or pharmaceuticallyacceptable salt, enantiomer or diastereomer thereof.
 2. A compound offormula (I) according to claim 1, wherein R¹ iscarboxymethyl(methyl)aminooxopyrrolidinyl,carboxypyrrolidinyloxopyrrolidinyl,carboxypyrrolidinyl(methyl)oxopyrrolidinyl,carboxyphenyloxopyrrolidinyl, carboxypyridinyloxopyrrolidinyl,carboxyphenylaminooxopyrrolidinyl, fluorocarboxyphenyloxopyrrolidinyl orcarboxymethyloxooxadiazabicyclo[3.3.1]nonanyl; R² is H or methyl; R³ ismethyl; R⁴ is trifluorophenyl; or pharmaceutically acceptable salt,enantiomer or diastereomer thereof.
 3. A compound selected from:(2S)-1-[1-[(6S)-6-methyl-5-[(3,4,5-trifluorophenyl)carbamoyl]-6,7-dihydro-4H-pyrazolo[1,5-a]pyrazin-3-yl]-5-oxo-pyrrolidin-3-yl]pyrrolidine-2-carboxylicacid;(2S)-1-[(2S)-2-methyl-1-[(6S)-6-methyl-5-[(3,4,5-trifluorophenyl)carbamoyl]-6,7-dihydro-4H-pyrazolo[1,5-a]pyrazin-3-yl]-5-oxo-pyrrolidin-3-yl]pyrrolidine-2-carboxylicacid;2-[methyl-[1-[(6S)-6-methyl-5-[(3,4,5-trifluorophenyl)carbamoyl]-6,7-dihydro-4H-pyrazolo[1,5-a]pyrazin-3-yl]-5-oxo-pyrrolidin-3-yl]amino]aceticacid;(2R)-1-[(2S)-2-methyl-1-[(6S)-6-methyl-5-[(3,4,5-trifluorophenyl)carbamoyl]-6,7-dihydro-4H-pyrazolo[1,5-a]pyrazin-3-yl]-5-oxo-pyrrolidin-3-yl]pyrrolidine-2-carboxylicacid;1-[1-[(6S)-6-methyl-5-[(3,4,5-trifluorophenyl)carbamoyl]-6,7-dihydro-4H-pyrazolo[1,5-a]pyrazin-3-yl]-5-oxo-pyrrolidin-3-yl]pyrrolidine-3-carboxylicacid;(2S)-1-[1-[(6S,7S)-6,7-dimethyl-5-[(3,4,5-trifluorophenyl)carbamoyl]-6,7-dihydro-4H-pyrazolo[1,5-a]pyrazin-3-yl]-5-oxo-pyrrolidin-3-yl]pyrrolidine-2-carboxylicacid;2-[1-[(6S)-6-methyl-5-[(3,4,5-trifluorophenyl)carbamoyl]-6,7-dihydro-4H-pyrazolo[1,5-a]pyrazin-3-yl]-5-oxo-pyrrolidin-3-yl]benzoicacid;3-[1-[(6S)-6-methyl-5-[(3,4,5-trifluorophenyl)carbamoyl]-6,7-dihydro-4H-pyrazolo[1,5-a]pyrazin-3-yl]-5-oxo-pyrrolidin-3-yl]benzoicacid;(2R)-1-[1-[(6S)-6-methyl-5-[(3,4,5-trifluorophenyl)carbamoyl]-6,7-dihydro-4H-pyrazolo[1,5-a]pyrazin-3-yl]-5-oxo-pyrrolidin-3-yl]pyrrolidine-2-carboxylicacid;3-fluoro-2-[1-[(6S)-6-methyl-5-[(3,4,5-trifluorophenyl)carbamoyl]-6,7-dihydro-4H-pyrazolo[1,5-a]pyrazin-3-yl]-5-oxo-pyrrolidin-3-yl]benzoicacid;2-fluoro-6-[1-[(6S)-6-methyl-5-[(3,4,5-trifluorophenyl)carbamoyl]-6,7-dihydro-4H-pyrazolo[1,5-a]pyrazin-3-yl]-5-oxo-pyrrolidin-3-yl]benzoicacid;2-[[1-[(6S)-6-methyl-5-[(3,4,5-trifluorophenyl)carbamoyl]-6,7-dihydro-4H-pyrazolo[1,5-a]pyrazin-3-yl]-5-oxo-pyrrolidin-3-yl]amino]benzoicacid;2-[7-[(6S)-6-methyl-5-[(3,4,5-trifluorophenyl)carbamoyl]-6,7-dihydro-4H-pyrazolo[1,5-a]pyrazin-3-yl]-6-oxo-3-oxa-7,9-diazabicyclo[3.3.1]nonan-9-yl]aceticacid;4-fluoro-2-[1-[(6S)-6-methyl-5-[(3,4,5-trifluorophenyl)carbamoyl]-6,7-dihydro-4H-pyrazolo[1,5-a]pyrazin-3-yl]-5-oxo-pyrrolidin-3-yl]benzoicacid;5-fluoro-2-[1-[(6S)-6-methyl-5-[(3,4,5-trifluorophenyl)carbamoyl]-6,7-dihydro-4H-pyrazolo[1,5-a]pyrazin-3-yl]-5-oxo-pyrrolidin-3-yl]benzoicacid;4-[1-[(6S)-6-methyl-5-[(3,4,5-trifluorophenyl)carbamoyl]-6,7-dihydro-4H-pyrazolo[1,5-a]pyrazin-3-yl]-5-oxo-pyrrolidin-3-yl]benzoicacid;6-[1-[(6S)-6-methyl-5-[(3,4,5-trifluorophenyl)carbamoyl]-6,7-dihydro-4H-pyrazolo[1,5-a]pyrazin-3-yl]-5-oxo-pyrrolidin-3-yl]pyridine-2-carboxylicacid; and2-[1-[(6S)-6-methyl-5-[(3,4,5-trifluorophenyl)carbamoyl]-6,7-dihydro-4H-pyrazolo[1,5-a]pyrazin-3-yl]-5-oxo-pyrrolidin-3-yl]pyridine-3-carboxylicacid.
 4. A process for the preparation of a compound according to anyone of claims 1 to 3 comprising the following step: (a) the reaction ofcompound of formula (V),

with an acid followed by urea formation with amine R⁴NH₂ in the presenceof a phosgene equivalent; wherein R¹ and R⁴ are defined as in any one ofclaims 1 to
 3. 5. A compound or pharmaceutically acceptable salts,enantiomers or diastereomers according to any one of claims 1 to 3 foruse as therapeutically active substance.
 6. A pharmaceutical compositioncomprising a compound in accordance with any one of claims 1 to 3 and atherapeutically inert carrier.
 7. The use of a compound according to anyone of claims 1 to 3 for the treatment or prophylaxis of hepatitis Bvirus infection.
 8. The use of a compound according to any one of claims1 to 3 for the preparation of a medicament for the treatment orprophylaxis of hepatitis B virus infection.
 9. A compound orpharmaceutically acceptable salt, enantiomer or diastereomer accordingto any one of claims 1 to 3 for the treatment or prophylaxis ofhepatitis B virus infection.
 10. A compound or pharmaceuticallyacceptable salt, enantiomer or diastereomer according to any one ofclaims 1 to 3, when manufactured according to a process of claim
 4. 11.A method for the treatment or prophylaxis of hepatitis B virusinfection, which method comprises administering a therapeuticallyeffective amount of a compound as defined in any one of claims 1 to 3.